Hope that you were joking when you said that you threw out the 3143 crossover....
someone on eBay would pay you a few dollars for them, I'm sure . Sounds to me like you are going about this correctly, I really like your choice of Audio components (Dynaco Stereo 35 and Heathkit UA-2) as well as your tweeks (Dueland caps and Mundorf resistors). For crossover resistors, I like to use the Mills MRA-12 non-inductive wirewounds as they are dead quiet and super reliable. If you really want a good tube crossover, check out a Marchand XM-126, it's all analogue, three or four way (12AX7 tubes ), and seperate power supply. They don't come up too often on the used market because most people keep them. http://www.marchandelec.com/xm126.html In any case, good luck with your 4343Bs, I've been loving mine for over 7 years!.Paul, Providence, RI