I'm just starting out, same as you - but one thing I found helpful was to draw smaller sized ovals onto the would be cab before grinding anything.
In other words- first draw your girdle line , like Jason suggested, but then say you have a 1 5/8" oval cab you want to make.
Take a magic marker & draw maybe a 1 3/8" oval on the top & then a 1" oval on the top & then a smaller one on the center.
Then when you start to grind , make a grind between the first 2 lines , not taking away your girdle line.
Then cut off the angle left from the first grind & bring the grind to the second line you drew.
The center oval I found really helpful cause it makes you sure that you grind everywhere & not leave a flat spot on top.
Then when I move to the next grinding wheel, I coat the cab completely with magic market, again so I'm sure I grind everywhere.
ALSO, when you coat it with magic marker it's a lot easier ( for some reason I don't know) to see if your shape is weirded out. DAMHIKT.
And they are right, at least I'm finding out ,the more you do & the quicker you do more, the easier it gets.
I'm sure I'm out of the ordinary that I draw all these extra ovals on my would be cab, but I've found it a good visual reference to go from.
Hope it helps, it works for me.
Patty
