Heavy difficult to move speakers- how do you deal?

I really like what @lak said.  Most of mine have a place to screw in already.  But I am little weird about them sitting on casters from a purist standpoint.

use 3 of these

2" casters, need 3" height for dual layers of ball bearings

surface mounted top plate, use screws or two 1" x 2" ez pass strips

1" wide ezypass strips

2" x 4" clear, cut to fit

THERE ARE VERY SLIPPERY  SLIDERS OUT THERE - I HAVE 6  OF THESE UNDER MY DUNLAY 6 SPEAKERS (520LBS) AND I CAN MOVE THEM SORT OF ENOUGH TO GET TO THE CONNECTORS - THESE WOULD WORK GREAT UNDER LIGHTER SPEAKERS

I have never seen 520 pound speakers. That’s nearly 3 tons of speakers

The sliders will work but you will have to get the discs under the spikes before setting them on the sliders which is a PITA.

Alternative idea to move them only once for placement purposes:  get a piece of Masonite that is a few inches larger than the footprint of the spikes of the G5s and put the glossy side down.  Slide around until you've dialed the position, mark the spot then remove the Masonite.  Pro tip from a former mover:  Cut the Masonite in half, duct tape the two halves back together on the rough side, this will be the side facing up under the speaker.  Slide around all you want then when set, peel off the duct tape, tip the speaker to remove one half of the Masonite, tip the speaker the other direction remove second piece of Masonite and Done!