Yes keep the center of gravity LOW.....
No pedestals......swivel mounts directly to the bench seat tops.
Swivel mounts with steel ball bearings rust......find the type with nylon bearings. Mandatory if using in salt water.
After 10 years of use in only saltwater......they still swivel fine...
Have you looked at the capacity plate that should be affixed on the inside someplace?
It's a yellow colored metal plate that gives capacities and lists the manufacturer's name and model number.
From the model number, you may be able to run down more specs.
Good luck