15.5 privateer sole and stringer repair

I now have the boat stripped and ready to put in new stringers and sole. these are my questions for any of you kind readers who are willing to reply
1; this is a 1985 fiberglass hull, should I use polyester resin to save $ or epoxy?

2: would solid spanish cedar be a better stringer material or should I go back to original marine plywood encapsulated and fiberglassed?

3;What do people mean by not letting the stringer connect with the hull to avoid a hard spot?

4; what type of fastners should I use to screw the sole to the stringer with? Brass? Thanks