Will you be compromising the heating in the room by exchanging rad for rail?
For example the difference between even small single rad of say 400mm x 800mm and an equivalent sized rail will be around 600 BTUs.
A small double glazed bathroom, say 1.8m x 1.5m x 2.4m could require about 920 BTUs.
I'm pretty sure I'll be able to plumb it in, the filling & drilling won't be a problem! So might as well give it a go...... whats the worst that happen - flood the house!? ha
Lots of things can happen whilst plumbing, flooding due to leak, ceiling comes down, carpets get wet, fire if soldering joints, oxygenate the system causing corrosion to rads and boiler to name a few.