Hi Rajacat,
With biwire cables you would be able to bypass the jumpers and this would only work in 4-ohm mode.
I do like the dipole better for exactly what you mentioned and you’re right on about the differences. I do change from one to the other, but tend to listen in Dipole more.
If you have short stand and can tilt the speakers back a little for even better soundstaging.
A little higher power would be better in a SET. 300Bs are very good and Welborn is a great amp. You can try a used wavelength Duetta if you can find one. For a 2A3 I would look at the Sun Audio. It’s sounds like it should be more than 3 watts so this amp would work, but I’m pretty interested in the Sun Audio single ended EL-34 amp.
Not SET but very surprising is the new Dynakit ST35. It’s $495 as a kit and worth every penny.
Thanks again,
Louis