Would you recommend I go with the 5'3"(up to 210lbs)? What would be the downside for the lighter kids - maneuverability? What happens if someone is over 210lbs - trouble going ropeless?
Thanks!
You've hit the nail with both issues/tradeoffs on any particular surfboard. The bigger, more buoyant boards are less maneuverable, as a rule, and when pushing the weight limit of a board, going ropeless becomes more difficult.
We only have one board - a very buoyant Red Rocket by Inland - one of the orginal red ones
My little kids can surf on it ropeless, even without balast on my sx230 - IF they can get up on it. The challenge for a lighter weight person on a buoyant board is the technique/method employed to start out. Because the board is so buoyant, one of the standard ways of starting (floating in the water, on your back, with your heels on the board, and the board flat on the water; then pushing down on your heels to turn the board sideways, as the boat puts tension on the rope, and then being pulled out of the water) is very difficult with a buoyant board and a person of little mass - they can't push down hard enough on their heels to flip the board sideways.
Some of my kids have gotten the technique of holding the board sideways, with one/two hands, while holding the rope, while putting their feet on the boards, while floating on their back (yes, it is as difficult as it sounds - especially for someone not super comfortable in the water or without a lot of experieince).
For my littlest kids/beginners, I have found if my older son floats in the water with them, and holds the board sideways for them, then they can get out/up pretty easily. Or sitting on a tube with their feet on the board would work. Or starting from the back of the boat (but this brings its own challenges - so I don't recommend young kids doing that).
BUT - if the kids can get up on a buoyant board, they can go ropeless much easier than a heavy person!