Mine is a true Windom which I finally got working on 80, 40 and 20 but with an L net match.
All three wire elements, short, long and feed line, are critical, height above ground.. Just about everything. Going to put the results and MMANA calcs. on my Previous Windom thread. The measuring, cutting, reconnecting and number of trials is not for the faint hearted. Burndy solderless connectors are very handy, to say the least.
Another thing I found was minimum capacitance in an L net should ideally be zero, not some 30pf or so found in a real variable and misc. wiring.
I'll release a set of impedances and SWR (vs. 200 ohms ) matching values found. Used 200 ohms because a lot of literature mentions that value if using coax feed like yours, Gary. I may do that but the single wire feed is working fine. Don't be scared by all the advice and broken dreams out there including having to have huge ground fields, but of course some is required. I'm pretty sure the 300 ft. Of buried AC line to the house is doing its share along with my connected to neutral piddling ground system.
Another neat thing is that the far field lobes are smoothed and nowhere near as sharp as imagined particularly on 40 and 20 but with peaks of 6 or 7 dbi. 80's field of course is just a big nearly circular blob. Because of true Windom's open wire feed vertical component, 40 and 20 have surprisingly low radiation angles for those not so narrow lobes too.
One thing I did learn; feeding any Marconi or derived system on anything more than a single freq. is closer to " art" than science. ...and an arcane art at that.