I have some track lighting with low voltage heads. I figured I could replace the current light bulbs with LED. Does this usually work? I am also thinking that the track heads have electronic transformers. Not sure how they react to a much lower load? Also, can I still dim the whole system?

I build lamps as a hobby/side business. I make them out of cigar boxes using a dimmer switch to control the bulb(s). I am using a Lutron Rotary 5-Amp Preset Dimmer, purchased from Lowes, Model D-600PH-DK. This runs to a Pass & Seymour 660W Rubb Lampholder. Everything works fine, but the problem is that the center post on the dimmer switch is generally not long enough to go through the box and into the knob, while still allowing the push on/off function. My workaround so far has been to drill a hole that is slightly larger that the knob. I want to be able to drill a hole just large enough for the dimmer post. That all being said, I can not find a dimmer switch with a a longer post. What I have found are that potentiometer's have a long enough post for my purposes. My question is, is there a type of potentiometer I can use that will act as a light dimmer safely? Please see an example of my lamps below.