Update. I have completed continuous distillation of about 100 litres-worth of 12% ABV feed,  taken in 10 to 12 hour sessions of 4.5 litres feed each. Output from my carefully QA'd and easily-repeatable sugar-boosted malt feed is taken off at 92% ABV, at which strength I get my preferred composition of "maltiness" and NO heads or tails whatsoever. (They are removed at high efficiency by the still). Output volume is roughly 500mls each run and this typically yields ~1,100 mls of 40%ABV s