Who would have thought?
By giving extra tools, one of the Oblivion levels can qualify for a part in the less builders challenge! To be exact, Temple Of Oblivion. Castle Of Oblivion doesn't have the right terrain, and Oblivion already has the fewest builders it can.
With 30 Floaters, 30 Blockers(I only used 29 though), 1 Builder, 5 Bashers, 5 Miners(well 3 actually, maybe even 2, but I'm going to give 5 in the release) and 5 Diggers, it is possible to acheive 30 out of 30 on Temple Of Oblivion! It took me a few attempts to find and execute this solution correctly though. The good thing is though, it involves no precision or timing operations, except the low-medium (somewhere inbetween, lol) precision required for the Oblivion trick. (Yes, even though it's a fewest builders challenge solution, it still uses the Oblivion trick, PLUS more freed blockers that aren't part of the trick)