If you don't want to pay big bucks for that big scope, this is a
pier mounted; Russian equatorial mount with a single drive.
I have had a professional machine shop modify the mounting to the pier so it is "rock solid". I never used this mount as I ran out of money (lost job) before I bought the big scope. (I wanted a 10" F6)...I can sell this BRAND NEW mount for $250, plus shipping in CONUS (this is a beefy mount)
Pictures can be seen at the TALscopes web site (this is a new GEM2RA mount in wooden box). It can handle scopes that require a GM11 type of mount, such as a large Mac, Mac Newt, Newt, or Schmitt. The payload is 3 times that of a Polaris at one third the price!...The set-up is pretty quick also.