I haven't raced flat track at all, and haven't done much quad racing at all.... However I have done quite a few sport bike road courses.... So heres my 2 cents... Take it as you will, not bashing you at all so please dont take it that way. Just offering a little info from my experience....
I watched pretty much every second of those vids beginning to end and never saw you hit the front brakes once... What they taught me in racing school is the race is won on the brakes. Brake later, brake harder, and you will improve your times. With a blaster this improves that much more because its a extremely LIGHT quad. Try staying on the throttle a little more into the turn and the tape the brakes to transfer the weight to the front and make turning/sliding easier. Hard to tell from the helmet cam but doesn't seem like u are leaning very far off either...
All in all great job man! I'd love to do some flat track racing and will do it one day! Thanks for sharing the vids! Rep given!