Thanks guys, that's exactly what I was looking for from they guys I wanted to hear it from. It sounds like I'm on the right track. In motocross I used to shift alot when I rode smaller bikes to keep them in the powerband. I didn't know if that's how I should ride the r3 or not, I didn't want to blow the thing up. A few times I went into long sweepers around 6000 rpm and then I downshifted on exit mid turn to get more exit speed out of the turn, but maybe I should down shift 2 gears entering the corner and keep it above 8000 rpm thru the corner. On long sweepers, what rpm do you have the bike at? Is it ok to stay above 8000 or 9000 thru the corners? Is it more dangerous? Or not a big deal since its a 300.
Do you guys use the rear brake at all? I have a bad habit of using it. I try to out brake the bigger bikes by staying on the gas longer and braking harder, It works in the c Group because everyone coasts into the corners. Hopefully I'll use the brakes less and less as I get used to the track.
I'm still pretty slow, but I did follow an instructor for 2 sessions and once I learned his lines we started passing some 600 and 1000's in the C group. (the slower guys) The funny thing is it actually felt like I was going slower, but I probably dropped 10 seconds off my lap times by taking the right lines.
Hey Capitalview, If you are racing at 210 lbs, don't you feel like you are at a huge disadvantage against the lighter riders? Do they pull you on the straights? Do you ever think you should move up a to a bigger bike? or is there a reason you prefer a 300 over a 600 or 1000.
Personally, I'm thinking of maybe moving up to 600, I think my laptimes would drop if I was on a 600. Will riding the 300 make me a better rider, or will I just have to work harder to go as fast as a 600.
I wouldn't worry about being leaned over and being at high revs. You are only leaned over for a couple of seconds.
Definitely keep the revs up going into the corners. You can up shift mid corner if you run out of RPMs. Just be careful in left hand turns if you are using standard shift pattern and stock foot pegs. You may end up hitting your toes trying to get under the shift lever. It isn't a big deal, I have hit my toes a number of times even with rear sets. It just takes some getting use to.
I don't usually use the rear brake. Unless I end up in the grass. Front brake in that situation is, almost always, an instant fall. I am going to try to test using the rear a bit this coming year though. Just to see how it works out. Most mortals don't touch the rear brake though. Nothing wrong with it if you know what to expect out of it. Just don't lock it up.

If you watch Moto GP or World Superbike you will see them use the rear brake all the time.
You want to keep as much speed up through the corners with these little bikes as possible. That is one of the really nice things about these bikes. They really teach corner speed. I know it sounds obvious, but the less you brake the faster you will go. Just be comfortable when you are doing it. Track days are NOT races. Use them for what they are, a time to learn how to ride better. Don't worry about lap times right now. Work on body position, learning the track, looking through the corners, and being smooth.
As for my weight and other riders, I actually use to race a SV650. I wanted to go smaller. I have always had a thing for little bikes. Sure, a light weight kid on the same bike with similar skills might beat me. Of course, s/he might do the same on the 600 or 1000. I do have a goal of losing 30 lbs this winter though.
As for the 600/1000 option, I have no urge to ride them. I consider them point and shoot bikes. They go through tires almost every weekend, are heavy, and cost almost two to three times as much as my R3. In both maintenance and initial buy in. 4 cylinders vs 2 cylinder, much larger and more expensive tires, more expensive exhausts, more oil, more fuel, etc...
On my SV, when I did track days, I was running in the advance class. It didn't happen as much then, but even on the SV the liter and 600 bikes would sometimes hold me up in the corners. I am currently running in the Intermediate class because of the slower lap times I do on the R3. The 600 and liter bikes drive me up a wall. They make up much of their quick lap times in the straights. The riders just don't seem to be able to figure out how to corner though. If I can get by a bigger bike in the first half of Blackhawk I will not see that bike again. A track like Road America, which has 3 really long straights, that won't be the case.
Yes, you will lower your lap times if you get a 600 or 1000. It doesn't mean you are a better rider though. It may just mean you can go faster in a straight line. Almost anyone can go fast in a straight line. The corners separate the good/experienced riders from the mediocre.
Instead of spending money on a bigger bike I would invest in better suspension and braided lines and better pads. At a minimum you will need stiffer springs for the front forks. Not sure if the rear shock can have a heavier spring put on it, but you will need that also to get the bike set up correctly for your weight. There are a couple threads in the suspension section on rear shocks and front forks. YSS has a couple cheaper ones that would serve well as a starting point. You could probably do front and rear suspension for under $1000 and it would totally transform the bike, both on and off the track. Heck, I bet you could do it for under $600 if you just wanted to do springs in the front and install them yourself and the cheapest YSS shock. I do have to give a shout out to
@forks-by-matt though. Very happy with the cartridges he put in the stock R3 forks. Plus at almost half the cost of aftermarket cartridges, and about the same cost as emulators, it is a heck of a deal.
One last, often repeated phrase, it is more fun to ride a little bike fast than a fast bike slow.