Proper mounting for metal rub rails

[DRB]

http://pic70.picturetrail.com/VOL1848/9515042/17350681/311750026.jpgI am considering the use of metal rub rails on my Simmons Sea Skiff 18 and would like to know how they are normally mounted when used on gunwales. I am considering useing some 3/4 x 1/8 flat stock SS or aluminum. This would be a fraction of the cost of half oval stock and is readily available with out the outlandish shipping fees that I would have to pay to have the half oval shipped from florida to the west coast. I would need to drill and counter sink holes and polish them up a bit. they would not be as nice as half oval but would not look to bad. I used this method on two drift boats for chine gaurds and it worked well. They take a constant beating against rocks and hold up well. On the drift boats I took the advice of experienced builders and used no caulking to bed them. One boat has SS fastened to oak chine strip with #6 x 3/8 ss screws and the other has aluminum fastened to Ipe chine strips and again, they have taken a beating and held up well. My question with the rub rails is weather I should use bedding and if so what type? Do they need to be bedded on to bare wood or can I put them on top of the paint later on if I decide to? Also, should I try to seal the screw holes with something? I think that I would need to use longer screw as the Doug fir outwale will not hold screws as well as the Oak an Ipe and will also be less Rot resistent. I also have access to purple heart at a very reasonable price and have thought about useing a strip of that either by it self or capped with the flat stock.
What do you think?

[Mrleft8]

You've got a nice boat there. I'd spring for the half oval. But I'd get it from Maine, not Florida... ;)
I'd bed anything you use with Dolfinite natural. If you take a syringe and shoot a little varnish, or CPES into the screw holes before you send home your screws you won't regret it.

[Tylerdurden]

If your good with a grinder Use a Flap disc to round the edges.
Drill press the flat stock and use a cobalt bit for the holes then follow up with a carbide countersink. Use lots of oil.
I would price out the countersink and factor in tour labor before going to flat stock though. You may fine the effort isn't worth it.
I think I would only use it if I had the flat stock on hand.

Of course if you are going with aluminum none of the above apply's.

[Peter Malcolm Jardine]

I have all half oval on my Chris Craft of course, and you can get it solid or hollow. I like the look, and I recently removed all of it, buffed it, hammered out a few dings collected in the 40 plus years, and remounted. I used existing screw holes, but syringed them all with CPES as Lefty suggested, and then used sikaflex to bed around the screws. I sealed the entire edge with CPES, then painted it, two coats, then remounted the rail. I always dip each screw in caulking, as well as a blob around the hole, then clean up the over flow in the countersink after it's done.