I'm pretty much in the same boat as you are...even though my boat isn't even finished. I've been taking it down some rapids and swift water. Lots of rocks, dings, dents, and scratches. Sometime around January I'll be very aggessively sanding the hull down to the fiberglass with out sanding into the fiberglass. Then I'll add another full layer of 4 oz., possibly 6 oz s-glass cloth for better ding and impact resistance. You might want to look at the s-glass cloth rather than multiple layers of e-glass. On my boat, in fact, most of my boats I don't go for museum quality finishes. I do what I call a utility finish...because I use the boats hard...not abuse...use HARD.
Taping the edge of the deck should work fine...even if you have to feather and then varnish the entire boat.
A spot patch and sand should work fine on your boat. I do it all the time.
One of these days I'm gonna build one of those museum quality boats just to show off...but I'll continue to hit rocks, stumps, and other unmentionable stuff with my workhorse boats.