between v blocks,i've always used a small press,(9t),3" alloy block to spread load,whatch you don't flatspot legs,(if thin wall forks like Rickman,bail!!),keep the v blocks a fair equal distance apart,index high spot with texta,press through opposite bend,it's just diminishing returns till forks are straight,if serious use dial guage,but like truing wheels, by eye's pretty good??(well mine is,
),rotate legs in blocks using the arbour as guage (just a poothteenth off),it's not rocket science
,good luck