Bob, maybe you can extrapolate from the following info, or narrow down yr choices... Pls note that I listen to classical music mainly and blues, so my opinion is biased in that respect. Also, it's my ears and tastes, i.e. YMMV.
First: your amps are arguably neutral, you like the sound, they're open and have driving power; so, there should be no problems getting the speakers rocking...
Of the speakers you mention, I had the Avanti & have heard the Piega. I have enjoyed both (i.e., was satisfied by the sound)partnered with the following ss amps: Symphonic Line RG7, RG4 (monos), Kraft 250 classA: "warm", euphonic, and fast transients, good tonal balance; Burmester mid-line (name?) amp: precision, clarity; YBA Passion stereo: dynamics, similar to Kraft, but slightly more neutral and less "euphonic"; ML 360(? The big 150W stereo.. I never remember the numbers): fast, bit darker than the others, I preferred it on blues than on classical.
Overall, the Kraft 250A pleased me the most with both speakers.
Both speakers had good, easy, bass response to around 40Hz in the room, with the Avanti being more demanding of positioning in order to overcome an ever so slightly analytical lower mid. The Piegas erred (for wont of a better word) slightly towards neutrality while the Avanti towards brightness -- both pleasantly so, and I may say intentionally (& thereby, achieving an excellent balance). I found the Avanti had the edge on imaging and the Piega on sense of space. Piega reminded me slightly of a hybrid stat (a good one, of course!), while the Avanti have speed and sound very phase correct, top to bottom.
Not very decisive, I know, but if you could hear one of these speakers, we can then compare notes. Cheers!