Some people have reported using the 2226J in a modified design, but I have not seen measurements of such a speaker, nor have I made any measurements myself. So I don't know how much of a change there is.
People that modify the crossover for a 2226J double the inductor values and half the capacitor values in the woofer circuit. They also attenuate the tweeter 3dB to match the voltage sensitivity of the 2226J. This is done by changing R1/R2 values as shown in the chart below:
I've not heard the HTM-10's. There are a number of threads on other forums that go into detail about the DIYSG speakers and their designers seem well spoken and diligent. There are many folks that have built them that like them.
Thing is, you already have the 2226h woofers. These aren't the entry level woofers for the 4 pi's but the full blown upgrade woofer. They are also the single most expensive part in the 4 pi build - about $1000 for a brand new pair. It's a great woofer even when you have to buy them retail but you already have them ... IMHO it'd kinda be a shame to ignore them.