i have a super polaris i can get if i wanted it, but the SSK2 doesnt like ascom- id forget about the vixen go-to stuff unless you get into the new spinx mounts- as far as the EQ5/6- the '6' would be a better choice, even that has smaller tripod legs and a counterweight bar then the mid sized ASGT mount- when i contacted skywatcher, they told me the EQ6 and Pro series are the exact same mount- only thing different on the Pro series is fancy knobs and white paint- so i would say the EQ6 (pro or standard) is the best capacity synta mount- though not the best choice for AP- reason i say the 6 over the 5, heres a link comparing the ASGT and HEQ5 mount
http://telescope-service.com/mounts/...t.html#ADMComp