Gary,
If you're hull is already glassed (I took that to be so from your message and when I did my deck glassing my hull was already glassed) and you cut the glass from the deck where it overlaps the tape you will probably not have any noticeable lines left. I figure this because you will be no doubt be doing some sanding and fill coating in that area anyway. That coupled with the fact that you are probably going to do it very cautiously should make for a good end product.
I was very sloppy when I did mine and have not yet sanded it completely and it is not as noticeable as I thought it would be. I did not use any tape masking, just simply lapped it over about 2 inches or so and wetted it out, strings and all. I think you have a good plan that will turn out to your satisfaction and much better than what I did.

I built my kayak with looks being the least of my worries. I am not even done yet (still have some sanding, more epoxy and painting) but have taken it on two paddles and got tons of compliments on "the beast". It pales in comparison to all of the boats I've seen on this site and still I had this one person (a carpenter by trade) drooling over it. So to repeat what I have heard over and over here....do your best and you won't believe the compliments you will get on it.

Good luck and let us know how it turns out.

--Tony

: I am about to do my addition of Glass to the deck of my S & G Tandem.
: This is a first for me. I am concerned about the best way to trim the
: Fiberglass edge overlap onto the sides of the hull. I am planning on first
: adding blue masking tape 1.5 inches down my hull. Then, I plan to add the
: glass and trim to the tape line 2 hours after epoxy coating.

: I am concerned about cutting into the hull glass and leaving a cut line on
: the sides of my hull.

: Please provide any suggestions you may have.

: Thanks,
: Gary