I do deadlifts and squats on separate days from each other, and usually do leg curls on a swiss ball after squats. I don't have a GHD or even one of those benches with a leg curl thing. The swiss ball can't be loaded in any way though, so it's basically just a calisthenics movement.

I took a chunk of 2x12 and attached 4 fixed caster wheels to it so it only rolls in a straight line.

You can set up like a floor slide and do hamstring curls, but the plank can be loaded with plates.

It looks silly, but it's easy on the knees and back and slams the hamstrings, should be better assistance for the deadlift than just using the ball.

If its a stupid plan, but it works, then its not a stupid plan.

Ham and glute stuff with a barbell is hard without slamming the back too, and my back gets hit hard on deadlift day.

I prefer free weights, but I can see why the bros use a lot of machines too.