Most 2-way speaker kits are in the 87-88db efficiency range, including your TriTrix (as well as the Solstice). In fact, most manufactured audiophile speakers are in this range as well. There are some super efficient speakers like Klipsch and Tekton, but they are the exception.
If you want efficiency, take a look at the MarkAudio 12P full range 8" driver. It’s not going to have the high frequency extension and attack that tweeters do, but it’s very natural sounding and has good low end response and it’s very efficient at 91.7db. It’s also easy to drive by an amplifier because it’s rated as 8 ohms. If you look at the impedance graph, it doesn’t actually drop below 9 ohms so you don’t need a big powerful high current amplifier. However, you’d have to build your own cabinet. The slightly smaller 10P driver is also great, but not quite as efficient. For what it is, it does an exceptional job and you don’t have to worry about crossover design. I built a 12P center channel and it does an amazing job for a full range driver.
There are other very high efficiency full range drivers, but they all have problems of one sort or another (such as extremely breakup at a certain frequency or a tilt towards the upper mids/high with thin bass). The MarkAudio is one of them that does the entire frequency range right.
The MarkAudio metal cone full range speakers do have a bit more high frequency, but they also sound a bit metallic and bright/harsh in comparison because of the breakup problem on metal drivers.