I'm a fan of oil. Varnol in particular, or B&Q Decking oil for lower budget applications. Especially for floorboards. Protects, is easy to top up and is less slippery than varnish. Only needs topping up where it's worn, so applying from the top works OK.
But I have yet to get a decent finish on varnish, just haven't got the patience and technique yet!
Tim
I have been advised to oil them on a regular basis. What would other suggest. Do I need to oil them? and it so can I get away with doing it from above, they are semi permanent and screwed in place.
James