Through my experience, I would not match a typical low powered SET amplifier with any speaker less than 100+ db sensitivity. While the amps may drive the speakers, they most likely will not drive them as the speaker manufacturer intended. You may hear wonderful midrange, but bass and dynamics will suffer greatly.
Please also take into consideration room size. If you are in a very small room, you might be able to go with a little less sensitive speaker.
Please also take into consideration room size. If you are in a very small room, you might be able to go with a little less sensitive speaker.