Hi Greg
I regularly run my FSQ/QHY9 rig on a HEQ5Pro. Guided using OAG and very happy. For dark sky trips prefer to use this mount over EQ6 - lighter to pack and performance at least as good.
The Tak deserves a nicer mount and camera, but my lotto tickets haven't been successful lately.
The chinese mounts are likely to be more variable in QA than you're used to with high end mounts. Perhaps arrange trial/return if you buy?
The newer AZ-EQ5 and AZ-EQ6 belt driven mounts are supposed to be very good. No experience with them myself. EQ6-R in same class if looking at EQ6 size.
Some past images of this combination here:
https://goo.gl/photos/d9wEjmDRM89dE8nD7
Would be very surprised if the HEQ5Pro couldn't handle a large lens rig.