Upgrades, Parts, And Maintenance On An S2 8.0B - Advice Needed

[Eihli]

I'm in the process of really fixing up an S2 I bought last year and I was wondering if I could pick your brains for some thoughts on supplies before I start ordering parts.

I took down the mast and I'm replacing all the wiring and lights in it. I had the brilliant idea of using a 100ft extension cord from Lowes to run my electrical up the mast. Luckily it got caught and I gave up and while searching around online I found that I needed to get tinned copper wire.

1. I plan on ordering this stuff for the mast wiring:
16/2 AWG Marine Duplex
Good?

2. I had to replace my batteries. West Marine had starting batteries on sale and they were half the price of deep cycle batteries, so I'm running everything on the boat with starting batteries. Will I end up regretting that later? I don't plan on draining the batteries to less than 1/3 charge before they are hooked back up to shore power. The only thing I use underway is depth finder and nav lights at night.

3. I'm going to replace my halyard/sheets. I think I've got 3/8" halyard and 1/2" jib sheets right now. I planned on using this:
XLS Solid Color Yacht Braid - Red - 3/8 inch
for everything. Is that a decent rope at a decent price?

4. Are steaming/masthead lights fairly universal? Would you recommend anything from this page:
Steaming / Spreader / Deck Lights - The Binnacle: Your Complete Online Marine Store

5. My old steaming light is riveted to the mast. When I change it out, there will be holes in the mast. How should I seal those holes?

Thanks for any advice.

Cheers,
Eric Ihli