I tried subwoofers with Magnepan 0.7's with no luck. I wired them up with a pair of DW-M bass panels which filled in the lower frequencies with much better integration. I connected the 0.7's to the 4 Ohm outputs on may Hammond 1642 SE Transformers and the two 4 Ohm elements in each DW-M in series and in phase with the 8 to 16 Ohm transformer outputs.
In my weight training room I built a 45 SET which uses Goldwood GT 1118 pizo tweeters mounted in Parts Express 294-2924 horns and DS1B PRO-X6BM speakers with first order crossover 0.3 mH chokes. This kind of speaker system does well with a subwoofer.