First things first. :welcome: aboard Captmo47. Always nice to have a new member...
Remember, with a single post type seat arrangement, you have to mount the base very solidly. All the torque and stress is working at the base where the post inserts. And that can be a huge amount of leverage, So the base has to be very well mounted in solid material. Other seat mounts can spread that stress over a larger area and alleviate that torque better. But lots of boaters use single post arrangements and have no problems. Just something to think about...