I haven't but a bigger, heavier, longer air cooled bike will be no match on the race track and likely cost a lot more trying to make it competitive.
But! Trailblazers did what they did because they didn't listen to people like me!
I have helped prep both a R3 and rc390 track bikes, both made almost the same power on my dyno (40). Both started close to 30 before the usual pipe,airbox mapping mods and then a ton of suspension work etc. I would bet the sixty2 would be close to 35 to start and easy to get more than 40. the problem is the others have small and light engines and the sixty2 is probably close to 140lbs so I dare say double the weight.
Suspension will be even with both in that they all need $$ thrown at them to get competent. I have not had hands on the sixty2 but would think it will win the power wars as well as the durability but weight will be the problem. Little bikes are just fun and if you get a pack of them you have a race, someone needs to figure out how to get the sixty2 down to a wet weight close to 325 without doubling the cost of the new motorcycle.
That would be a fun thing to do. I would bet the Sixty2 could be made competitive on tight tracks where torque matters. As far as wright goes the little 300 are actually a little porky. Yamaha claims a wet weight of 375 for the R3 and Ducati claims 403 for the Sixty2. A lithium battery, exhaust, maybe some BST wheels and you’re there.