Replying to Grab's with spins

Hey
I've sking more than ever this year and I finally broke through the mental block of spinning past 3 and learned 5's 7's and almost 9's.  Now that I have them down I wanna start grabbing and corking.  I read a lot about cork 5's pop carve looker under arm/at your heel and spot the landing.  I'll test that out this weekend. 

I just need help with grabs on my spins.  I tried a saftey 5 last weekend and stop at 180 for some reason, then hucked a big spin, did the sfatey grab and made it 270 and landed on my side.  I guess my spins aren't good enough to try these yet so is there a way to progress into a grab?  I'm not sure if there is because really if you hit something there's either straight air or grabs, no real inbetween.  Any tips on this shitty problem?
Cheers
-aaron