Framing tub skirt

My new bathtub doesn't have a front skirt... it has a downward-curving lip. The examples I've seen all seem to involve building the skirt wall first, then lifting the tub over it and lowering it on the other side.

Is there any particular reason why I couldn't install the new tub without the skirt wall in place, then frame the skirt wall from light steel ~3/4" shorter than it needs to be, slide/tilt it into place under the front lip of the tub, then slide a 3/4" thick pressure-treated 1x4 under it to shim and raise it to the right height before bolting everything into place?

It seems like it would be a LOT easier to install that way... I'd have easier access to the drain for installation (a big deal, since the skirt side is my only access because the drain side of the tub is against an exterior wall), and the tub wouldn't have to be lifted as high -- from a dangerous-to-lift cantilevered, leaning-over position -- to get it in place. It's a 72x42 acrylic tub... not impossibly heavy, but heavy enough that trying to support its weight entirely from one side and lift it ~24 inches wouldn't really be a good idea unless there's some urgent & compelling reason to do it that way.

You can frame it after. A section of this is often made to be removable. If you are tiling it, you can get some high-strength magnets designed to temporarily hold it in place, and then you use some grout colored caulk to seal it in place. if you ever need to open it up, you cut out the caulk, remove the panel, and do what you need to do. www.schluter.com makes some magnets designed for this task.

tub

From the size you mention, that tub is probably designed to sit ON a platform at least slightly larger than the tub. IF it were designed to have a skirt fitted to it, the manufacturer would have one listed as an accessory.