For my Hilmans I purchased some really thick closed cell rubber that is used for cushioning, like anti fatigue matting, I think it's probably 3/4" thick? Anyway, place one square on each roller and when one gets a little unloaded it will still tow along nicely., instead of just staying behind. They really transform the experience if you have something heavy enough to need 4. If you can get away with 3 it makes it really easy to steer the equipment as it's being put in place.
I know this isn't possible with everyone, but in my shop where it's tight in places I put an heavy anchor bolt in each corner of the shop floor. This way I can use lever chain hoists with long slings to grab onto whatever I'm moving and move it very slowly but steady with minimal effort. When it's 40,000 it's nice to just be able to move it exactly an inch when that is all you want, in exactly the direction you want. I love the steel roller Hilmans, they take the least effort when things get pretty heavy and you can actually roll them over things like expansion joints. A buddy of mine tried using the nylon version when he moved his Mori NT and they squashed with flats instantly.
I need a better "toe jack" however, but that is a different conversation...
Dave @ Nerv