You say it still isn't filled or straight? Maybe after the fiber coat put the rage on top but put it on thick and then cut it down. When I first started doing body work I would put the filler on thin or just enough (so it seemed) and I ended up cutting it down and it was never enough so I had to add more again and again and cut it down and cut it down (sometimes cut it too much). I learned to just put quite a bit on and cut it down so I dont have to keep doing layer after layer. It's hard to explain and maybe your not even having this problem, I thought I'd address it that's all.