To the OP, I can appreciate your concern and ultimately I doubt any text will make you feel comfortable, but here is my experience on extended top end.
I have nearly 3 decades on an 200cc yamaha IT, it is on it's third bore size, original jug, original rod, original big end. The hours on this engine are uncalculatable 1000's? I have never broke a skirt, gouged a jug, rattled a little end, honestly, the bike has never fouled a plug, I put a new plug in it at the start of each season after my winter freshen up and never look at it again for the season, the jetting is clean. This engine works its butt off running with the big bikes of today and yesterday, it has never left me wanting in any condition but running the sand down in SC where the big bores just out power it on the top end. I cannot find my original manual , so I've lost decades of numbers, specs and such,(sore subject, new shop, wife had it last, she admits it, no idea where she put it a few years back when we were moving stuff) but I know sometime in the 90's pretty sure early 90s I changed to Motul 800. I'm not saying buy Motul, keep reading.
I mix my gas 50/1 since that change from the Yamaha lube I used for the first years of the bike, pretty sure original spec was 24 or 32 to one. When I go riding where I expect some extended high rpm runs, I mix 40/1, that is the extent of my prepping my bike for that. That little engine is air cooled, yours is water, it spins with a hell of an overrev it lives its life likely 30% higher rpm than your bike at any given moment. When I run sand I'm running with a TT500, an XT600, a 426 and a kx250 the bike may run for 3-4 hours without ever shutting off it may be pinned wide open for durations that I still wonder why it doesn't just die.
The bottom line, if your plug has a good color print under your normal riding conditions, and you need a little more info, do some WOT pulls from 3-8k as Jakobi mentioned, but I suspect you'll see good color. If you want some mental assurance, run a tank of 40/1 during that race and have a great time!!!!
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