Since you already have them I might start by jacking up the floor as much as you can and reattaching what you have. Doing the solid blocks is a fair amount of work and you must cut them so they are a very tight fit.

Staggering them enough to end screw will be ok too, but keep them as close to lining up as you can.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.