Kowkow, The Pass x250.5 is not enough power for the Thiel 7.2s. I would suspect that one would probably even need the x350 for the 2.4s. Overbudgeting on the speakers has essentially left you speaker-poor for the rest of the system. Thiel requires top electronics to be satisfactory. Short-changing the rest of the system will make it very difficult for you to really get the Thiels to show their best. Having gone from Pass x350 to x600, I can say that power is required to get their effortless full-range sound. You should consider selling the speakers unless you forsee being able to upgrade the amp.
Mobe, For me, the 7.2s have remarkable bass with pinpoint accuracy. I can point to the exact position of the kettle drums and the gong and the double basses in the orchestra. The bass has speed and heft, without being boomy. However, the bass was the most expensive aspect to really optimize. It requires proper set-up, power, and cabling. I'm using Nordost Valhalla, which has remarkable bass definition and speed. Some say the Valhalla is a tad dry, but I haven't found better for the bass. Same for the Elrod Statement powercords. These have energized the lower frequency to give it speed and definition. Is this speaker too fickle? Perhaps. Some might say that at that price, you should be able to plug anything into it and be impressed. However, I have not found a speaker yet that has made me want to sell these.
Rob