@incx
what i meant was i'm not comfortable doing german grip; never was. most people use it though, i just never became comfortable with it. i wish i was though because there's more power in it as compared to french grip.
french grip might make a drummer more susceptible to carpal tunnel syndrome, but i think as long as you do it right, it won't be a factor which type of grip a person uses. imo.
besides, with the french grip, you're supposed to be using the radius ulna, and fingers most of the time, not the wrist primarily, because that's just uncomfortable.
(info came from jojo mayer's dvd btw. it's an awesome encyclopedia on technique.)
and oh, don't worry about speeding up your blastbeats. speed will come in time, with correct practice and dedication. feel is much more important. even the really fast people will tell you that. good luck dude.