I already had a bilateral conversation (not a QSO, unfortunately, hi) about that with Heinz, HB9BCB. He uses links for 15 and 17 m and traps for 20 and 30 m.
I have now decided to use links for those as well, because the extensions at the endpoint of the antenna would be too long to be practical; one would have to take off roughly 1,5*0,95 = 1,425m for getting from 20 m to 17m, and another 95 cm for getting from 17 to 15m. This would mean repositioning the rig etc., so it is simpler to lower the pole a bit, reach out to the links and open/close them.
For others who want to try that design, I attach the plan. This is basically the antenna described by Heinz here: Trap EFHW and Coupler, plus the links for 17 and 15m.
By the way, Heinz’ design uses slightly bigger inductors and smaller capacitors than the tiny SOTAbeams traps. This reduces the resonant lengths a bit, which I find a plus. 16m is a handy length. What is really nice about this design is that it is pretty stable in terms of tuning - other than verticals, you can leave the tuner at home.
73 de Martin, DK3IT