MoI suits my purposes fine : )

""""""holes cut through a solid cubic surface"""""

If you have slabs or plates with holes, the easier way waould be to delete the top and bottom faces only.

Then slide and move you holes around.

Selecting all the edges and boundary to run planar to reform a sold is trivial.

My tip is always keep your curves so you can modify and rebuild later.

Two good tips! Noted and thank you!