Talking space requirements:
A 36HP boiler takes up 3x3x4, plus 18 engines, plus tubing and spacing inbetween. Even at full heat it produces 144 MJ/t, and consumes 15.84 buckets of lava per 1000 ticks.
36 magmatic engines produce 144 MJ/t, don't require liquid transposers, and consume 8 buckets...