Dustyn Caudle on stock suspension and stock tires showed up at Cresson never even having seen the track before and raced his Grom for the first time and was only 6 seconds off of Ryan's best... Dustyn is 200+, but, he is a freakin' rider...
my advice would be to quit worrying about weight discrepancies and start riding the bike as hard as you can... that applies for minis and big bikes alike... no excuses...