Just did this a week or two ago. I have Dobinsons C59-223V variable rate springs (just a bit over factory height), which were sitting at 21.5" before the airlift bags.
Measured the space inside the coil, called airlift, and, sure enough, they recommended the slightly taller bag--9.5" bag, IIRC. Rather than getting the 60808, I got the 60926, which has the same bags, but also a heat shield (which I didn't need) and two pucks for each side (none of which I needed).
I undid my rear shock mounts (which means taking off my TT rear shock mount skids), disconnected the sway bar, jacked up the driver's side, put an axle stand in front of the rear LCA mount, removed the wheel, and realized I'd taken disconnected my shocks for nothing. Could totally get the springs out with the shocks still attached--tight but doable.
As per many posts in this thread, I drilled the holes in the lower spring perch way out. And then drilled a third hole and made it even wider (using dremel cutoff wheel to connect my holes). I still think the blasted holes are not centered on the nipples, but they're fine for now.
If I were to do it again, I'd stick bags and springs in place, then
_mark where the nipple hits the lower spring perch_ and then make a giant hole there--not only are the existing holes in the spring perches not centered on the spring, even the center of the perch isn't centered--it's enough to drive one mad. I need to go check for rubbing and maybe do some more drilling one of these days, which of course will be more of a pain now that I have lines in place that are basically glued to the nipples. . .
Connected hoses to bags using no clamps, just loctite 545 to hold hoses in place. Ran two lines up along my raised breather line and fuel fill neck. T'd the lines waaay up high so I can easily convert to two schrader valves if the shared air construct doesn't work out. Then drilled way up high in the fender trim, on the vertical part that won't get hit no matter how far up I tuck my wheel.
Filled bags to 25 or 30 psi--within several hours they'd lost about 5 psi (probably just from expanding and settling), but then they stayed there. Lowered them to ~5psi.
Wanted another .5" lift in the rear and had thought about buying spacers AND airbags, and am glad I didn't (thanks to this thread)--the bags alone with 5 psi did give me .5" more height in the rear. Cranked front TBs to match--now at 22" rear and 21" front, and that's about as high as I plan on going.
Some pics.
