Tekton or Klipsch

I have never had a problem with low volume level control using any of these preamps: Spectral DMC5, DMC6, DMC15. Crown SL2, Threshold FET1, FET2, FET10, Mod Squad Deluxe Line Drive, XiangSheng 728A or my current PrimaLuna Dialogue Premium.  But I will say the passive Mod Squad and the lower gain PrimaLuna are preferred by me.   There is also impedance matching to take into consideration, especially with the passive Mod Squad and the PrimaLuna.  They each like to see amps with large input impedances. 

Pick up a pair of used Heresys and if you like them but need "more" sell them ( klipsch heritage  sell fast in my experience ) and move up the line. The new forte sounded very good at Axpona  btw and is gorgeous. 
The Heritage  line can sound wonderful  but they tend to upper midrange thinness and can be bass shy in the wrong room.  Alk crossovers can aleviate much of this with their adjustable taps and if you really want  to go down the rabbit hole replacement mid horns help too. 
If you dont like the Heresy at all look to lively direct radiators like the tekton. Reference 3a speakers are nice and lively and can be pretty wonderful avoiding potential  horn issues. 

Although I have a Schiit Loki wired into the system I rarely use it, and by simply adjusting the level a little on the two REL subs (those adjustments are also rarely needed) I can make things sound right. The Heresy IIIs have a well regarded and seemingly very accurate range to their designed-in low frequency limits, and the drivers are mounted very close together which is maybe responsible for the coherent overall sound. Small fat boxes unlike anything else...and a bargain.

The Forte I or Forte II will give up little to the Forte III, and at a lower cost. Replacement titanium tweeter diaphragms smooth them out and matched capacitors for a xover recap are very affordable from Bob Crites in Arkanasas. A little dynamat on the horn bodies/woofer struts and cabinet bracing, both very easy, and you get even better. Not a hard job.

I heard a number of high-end speakers at an audio meet-up last year. The Forte easily hangs with them. Just as good as the costlier speakers I demo’ed, but a different flavor. If you like dynamic, Forte all day. If you want more laid back, I’d go with something else. 

Alternate might be A/D/S speakers. They are great bang for the buck. ADS 1090, 810, might be a good option. Excellent, although no longer in business. A local search might turn some up. 

I cannot speak to the Tekton, but I’ve heard only good things and would love to try them myself. You’d be out shipping if you returned them, I’d be surprised if you did given what I’ve heard.

As for efficiency and and gain, a couple of attenuators in line would do the trick a lot simpler than changing amps.