Glen , I had an IEQ45 and it was a great mount , it held my Istar 127mm f8 easily , but I had to buy a WO hardwood HD tripod as , as usual most Chinese mounts have tripods to short for longish refractor OTA's .
Your OTA will be about 1300mm long ? so you need either a taller tripod or pier extension with all the mounts that are easily available today ,, if you don't want to sit on the ground while observing anywhere near the zenith .
I recommend Ioptron's IEQ45 without hesitation .
By the way I love your build so far , awesome .
Brian.