Nice vid.

I use caltracks/sliders as well and to me it does look like they could be moved a tiny bit.

When setting them up they say to center them, but what they dont say so much is you need to be in full race weight and you need to compensate for the bit that the springs themselves will settle.

You could probably gain a 1/8 or better travel wise by dropping the springs and just using a bur/die grinder to make the slot longer without any cutting or welding.