[BBRMotosports]

r u sure about a .8 fork spring?
that's almost double the size spring from stock!
when i'd respring for my dirtbike, all i needed was a .02 - .06 jump over/under to from stock size.

That is correct, the bike is wsprung wayyyy to soft from the factory which is why the big jump to make it correct. Most 125/250F MX bikes are sprung and valved for a 150 160 LB rider so they are closer to the average guys weight which is why you didn't need such a big jump in spring weight.