Clamping form blocks will become necessary very soon but my old vice just doesn't have the size or versatility needed for this job - or many others for that matter. Picked up a Bessey 5" vice from Lowes which has a swivel base and swiveling jaws to enable optimal form-block orientaion.
Like a kid in a candy store I couldn't resist picking up a couple more tools that will - obviously - be needed. Vice grips will be modified into crimping pliers if I can stomach the ruination of a brand new tool in the name of needed capability. 4/8/11 Update: Decided to purchase fluting pliers made by Aircraft Spruce so Vice Grips can be put to use in thier native state.
The new 8" square should be small enough to get into tight spaces to set proper alignment of components like ribs.