Dan, yes, its almost impossible to give advice to newbies without making it more complicated than the manual, which nobody ever reads because its too complicated (g).
so I erred on the side of safety.
I love my router table, I'm learning to do things on it I once thought I needed a lot of other tools for, but it is without doubt, the most dangerous machine for novices that I have ever worked with.
the thought of a cutter coming adrift at those speeds gives me the shivers.
Rick, I have more `1/4" shank bits than 1/2" at this stage, they work fine as long as you dont expect them to to do manly jobs on baulks of hardwood. But the sleeve does need to be inserted flush with the collet mouth, with (as Dan says) an 1/8" or so clearance between bit and chuck.