I put quite a few miles on my bike, so my interval would be closer to every 2 years, not 5.1. Do you need to change the valve cover gasket? Yes, each time you take the valve cover off.
2. Many people do the work in these stages:
(a) Get access to the valves and measure and RECORD the valve clearance for each valve on a paper DIAGRAM so there is no confusion about which valve had what clearance
(b) For the valves that are outside of the proper clearance range ONLY, remove the current current shims ONE AT A TIME, carefully recording the thickness of each one on the diagram, before proceeding to the next out-of-spec valve
(c) Calculate the NEW shim thicknesses needed for each out-of-spec valve and mark it on the diagram. In some cases, an existing shim in an out-of-spec valve can serve as the ideal replacement shim for a different out-of-spec valve. Determine how many new shims, and what thicknesses, are needed
(d) Buy the calculated new shims
(e) Replace the out-of-spec shims with the replacement shims
An alternative is to buy a large "set" of shims, but that is costly at OEM prices.
For someone like a typical R3 owner, who will only need to do the valve clearances once every 5 or more years, doing the valve clearance check and adjustment himself is not smart. You cannot be "good" at remembering all the correct steps and good at doing them. There are also risks - like dropping the camchain into the crankcase, or making a shim calculation error on a 12,500 rpm engine.
The $400 for the class is hard to justify for 2 reasons:
1. Since you will only be doing this once every 5 or more years, you won't remember the steps and precautions between the 25000 mile adjustment sessions
2. $400 is MORE than your dealership would charge you for this service, and the dealership mechanic, who does this a LOT more frequently then every 5 years, will be far less likely to forget a step or make an error. My dealer charges around $300 Canadian I think, which means about $300/5 = $60 per year to keep my valve clearances in proper adjustment. So, my plan is to have the dealer do it.
The real question I guess I should be asking myself is whether I should keep this bike or trade it for another. All the service that's coming up will cost me around $1,000 if I take it to a shop (new fork and shock oil plus new seals, valve check, steering and swingarm check and lube). There's been a lot of bikes going up for sale in the $2k range, so figuring in the cost of what I sell this for and paying for all that service, I could get something a little faster and with longer maintenance intervals (like an FZ6).
Or, I could learn how to do all the service myself and save some money in the long run and keep this bike til it dies.