The problem is, you shouldn't be spending only 20 points; first, that's only 5 points in the old system, which isn't much; second, acceleration is supposed to take up a larger chuck of your budget this time; and third, your ships should have lower than usual acceleration for sure in this tournament anyways. I calibrated it with 50 points into acceleration giving a decently-handling ship for its size.
For the thrusters, yes, it is 100 h and 60 v (diamonds would be very difficult to use, so I would just lower the numbers if I wanted easier placement). However, a Cronus can fit 5 for it's 18 sections, giving it a very high ratio (0.28). While I know tourney ships are usually denser than that, designing ships with fitting thrusters on in mind should mean you can still a good ratio.
And we also have separate points for accel and turning?
Your 60/100 thing still makes no sense. If one thruster is 100 px away from another horizontally, but only 30 away vertically, you still want that to be illegal? Think of it like a chessboard, and each side of a sqaure is 100 px. If every thruster is 60/100 away from every other in each of two dimensions, it mean you can only have 1 thruster per 100 px tall row, and one per 100 px wide column. It turns into a game of Queen's Chess. Definitely not feasible.
60/100 px is still a lot. I suggest 40/60 ratio, and each thruster gets a boundary diamond with points at (60,0), (0,40), (-60,0), and (0,-40) relative to the thruster. Then another one can't be placed in that diamond.