The last gym I did I used a pull along bucket lift it didn’t hurt the floor at all. We just had to hand roll it through the doors.We set it up in between 4 of the HID’s and all we had to do was spin around in between them. We put foam pads under the outriggers so we wouldn’t scratch the floors. They have some of those pull alongs that you can reduce the width to fit through a single doorway.I have a job coming up to replace 400 watt HID's in a gymnasium with LED's. Scissor lift would be really nice. They won't let me bring one in there unless I lay 3/4 plywood on the floor to run it on. Doesn't seem worth it compared to just using scaffolding that they will let me roll on the floor as long as wheels are in good condition and won't damage the floor. They will have a thin protective cover on the floor either way, but already have this and use it whenever there is other then athletic activities happening on that floor.
We used those many years ago, the first ones had hand crank outriggers, so leveling was not a big deal, even would work on slanted movie theatre floors ( but seats would have to be removed) the second generation, were weighted and had to be trailered job to job. Those were self leveling, so the floor had to be reasonably level.About 10 years ago I managed to pick up a used Upright-brand lift. It tips up and fits in the back of a standard pickup and it fits through 30" or narrower doors and puts my feet at 24' when fully extended. About the only thing it does require is a pretty level flat surface.
Exactly, we had a job were they had beams that required tearing down the top two sections for every two rows of lights. The guys were very nervous about accidentally dropping a brace from that high up and damaging the floor. Ended up hiring professional scaffold builders to move it every time.Just remember scaffolding needs to be inspected and tagged, and you need a 'competent' person to inspect each day. With safety considerations added to the install time savings, I don't know of many electrical jobs where scaffolding is going to be cheaper or more convenient than a lift.