Personally I would not put the rekluse on the 500. Are you stalling a lot on the track? I would just run a bigger fly wheel weight. I have not rode a 500 with a rekluse, but have rode plenty of 500 smokers in my day with and without fly wheel weights added. I have rode a 200, 300, 250 smokers & 450exc, 450xc 4 strokes with a rekluse and I can say they are good for not wanting to use the clutch ever or nasty rocks or roots in the tight trees. I will not put one on my current 450, but........When I add a 300 smoker to the arsenal, I will probably slap one on that as it will be my goat bike.
I rode a 2014 KTM450xc over new years that had on it and I will say I forgot that it was there as I was riding the bike the same way I would without it. Clutch action is the same, idle is the same even when you back off the throttle you get the same response. What is nice is when you come into a rocky section with some nice ledges to go up, you can hit it without the need to crab the clutch to stop from stalling.