Drilling holes in a steel boat to mount hardware
is a really bad idea. A great plus point of metal boats is that they can be genuinely dry, leak free. Drilling holes gives you the same long term problems as glass/wood boats have with leaks
Whatever type of track you use, the best way to mount it is to weld mount points to the deck
. They should be stainless, with threaded holes to screw down your track. They can either be welded on top of the deck
, in which case the track will be slightly above deck level, or you can drill holes and weld in stainless acorn nuts flush with the deck level. This is a very clean set up.
Installing the track with a thin insulator - uhmw plastic strip is good - should be done if you go with the flush mount route