Solved this a bit ago, the equation for solving the aim on a moving target with projectile motion ended up being a quartic. Read a couple of blog posts that explained the problem and had to port some quartic solving C code to lua iirc. Ended up working perfectly and will for you as long as you read these posts thoroughly:
(Use fixed speed with a moving target for projectile motion)
P.S.
The equations used in the original post for modeling the projectile’s motion were not accurate to real projectile motion because I didn’t even know there was such a thing yet. If you do not use the standard drop = 1/2gt^2 then this will not work for you.