I understand where you're coming from Gav, I know, getting into AP is a bottomless pit.
Brenden is correct in what he posted.
I would suggest reducing the load if you're looking at the mounts you suggested.
The first rule in AP is that you buy the best mount you can afford, it is the most crucial part of the system, even if you have to lower your sights and go widefield.
A large SCT is very taxing on even the better mounts, at those focal lengths, if you intend to get seriously into AP.
