Mark, in regards to the potential wear point on the bottom of the hull, I have been researching methods of prevention as I have a fiberglass kayak on order. Some of the nor cal guys use helicopter blade tape since their sand and beaches are a little more rocky than ours. Its not cheap but it seems to do the trick for keeping the fiberglass from getting beat up if it incidentally drags across concrete/rock/etc. Its 14 mils thick which is a little less than 1/64", or about the thickness of 3 sheets of printer paper.
https://www.amazon.com/ISC-Racers-Ta.../dp/B004FKND3W