I expect the TA70 antenna to have no advantage and lots of disadvantage over a TA50 or compatible antenna. Starting with it may be much easier to better position the small TA50. I believe Trig published enough statements about the TA50 Compatibility to use it for 2020 compliance in an experimental glider and enough for TABS in any glider. The situation with a 2020 compliant install with a TN70 in a type certified glider is more complex (that distant sound is me beating my head against the wall). I would not want to use the TA70 in any other installs except with the TN70 in a type certified glider following the TN70 STC.

Unfortunately some glider manufacturers were installing the TN70 thinking it was needed even in experimental gliders. That fugly wall wart has caused more problems that it was worth. Other glider manufacturers, working with Trig HQ, have standardized on the TA50 antenna at least for experimental gliders.

I am not a fan of GPS splitters for ADS-B Out system that may already be hard enough to get working. But again, if you you believe they can be used and meet compliance needs the emphasis should be on flight testing the whole setup. Certainly folks are using splitters for Some installs that seem to work OK.

With 2020 Compliance, great you are using the pneumatic squat switch. If you don’t mind I will shoot you a link to some draft doc soon.