I was just looking at the Tower website and didn't see either a 40/46 FP or LA listed so, that being the case, I went to the OS webpage. What I found is that none of them are available.
You would have to go with the 46AX or, if that much power isn't really what's needed, there is the 35AX. The 35 takes a 10X6/7, 11X6 or 12X6, according to the instruction book while the 46 would use the 10.5X6, 11X6/8 or 12X6/7