An H build is going to be your cheapest option having most of the parts.
Just remeber it was an H2 that won the chamionship in 1990 , the Ls never realised their potential
Racers aren't much fans of the H1 swinger which I dont understand (except the weight saving) as if you look at MotoGP bikes the not only go for an over or under braced arm but with side infills too

Something that is destined for one of my H1 arms if not two

The stiffer the backend the more power you can lay down in bends and get away with. Recently seen an L model racer with a converted H swingarm on it and it was a pro-series bike, rider said it turned in quicker with a shorter wheelbase and he was able to get the power back on sooner.
MM!