How do you feel about a wheeled dolly permanently under large floorstanding speakers?

You could use herbbie's gliders that spike to the glider and are easy to move.

Thanks everyone. The listening area will have an area rug, but the rest of the floor is vinyl plank over concrete. Spikes are a non-starter, as they will go right through the vinyl. Okay if they never move, but no way I can walk the speakers on spikes, making holes all along the way.

When you suggest castors on the speakers, I assume you mean attached directly to the bottom of the speaker. I can do that and like the idea.

Thanks for the tip on Herbbies gliders. Never heard of them but might work. I'll look into it.
Rex

Douglas, to confirm.... you are suggesting I mount castors directly to the bottom of the speakers? I hadn't considered that but like the idea. Locking castors, easy to play with positioning and they won't move once locked. I wonder how thick the bottom of a typical speaker enclosure is... don't want to create a problem putting in screws.

What size threads are the spike inserts in your speakers?  If they are in the 1/4-5/16 range you should be able to find suitable casters that can bolt with locking  nuts directly to the installed inserts.  
You do not want a caster to break off in the moving process!

 I had a pair of Green Mountain Diamanté’s that I fitted with casters in the manner I described.  I was satisfied with the results.

caper, yes, absolutely, casters on the bottom of the speakers in place of the spikes. It works beautifully!

Note, it will probably yield a superior result to spikes; as I said, the (often) additional elevation of the soundstage is considered by the ear to be advantageous. You don’t even need locking casters - unless you have a downhill slope to your floor! ;)

Here’s another reason to consider casters; you can probably alter the front baffle slope to improve the speaker. The Vapor Audio Joule White speakers I have do not have perfectly even height of the casters - I intentionally altered their height. The rear casters have two additional washers, which lift the rear of the speaker slightly, adding a hair more forward baffle slope, and imo give the speaker even better sound. Of course, it’s completely adjustable, as one can add or remove washers to suit. Imo, that is a far more important adjustment than whether the speaker sits on a spike or on casters.

With casters you can quickly, efficiently, check whatever placement you wish, and I encourage you to not waste time. You do not need days or weeks to move the speakers to your preferred location. Move them several times in a day if you wish. You will dial in a much preferred result quickly. There is no advantage to wasting your life on it. If you want, change it back, etc. Take a piece of tape and make a mark or two for preferred locations. It’s simple.

Absolutely, use a lock washer for the caster to cinch down. Select a robust caster, and don’t be chintzy about it. On wood floors be careful, as the weight of the speaker on the caster as it moves can put a running compression line in the wood! You do not want a thin wheeled caster, but one with more width to distribute the pressure so you won’t get damage. Note casters that can handle higher weight, and still have width to be ok on delicate floors. There, I just saved your flooring. :)