I'm shooting at a distance of three to 5 feet with HD video cameras with generous bounced lighting (I've rented units in the past and I expect to do so on new projects, it will depend on what the rental house has in stock.) My home made version didn't use tracks but used Pneumatic tires on carpeted or hard floor surfaces Operators stood on the floor. The dolly I used was set up to run in a 10 foot circle and a home made boom reached overhead to get a top down view and a fixed unit on the floor looking up.
The two cameras on the dolly were set up in a diagonal line, one to he upper right and one to the lower left with the operator really only looking at the lower left monitor.
Does that help?