Again, I may be stating the obvious, but clean aid climbing doesn't have to be pitches of nothing but hook placements. You use hooks and body weight placements only when there isn't anything better - no matter where you are.
If you haven't got a selection of traditional climbing protection, I'd start there if you are gung ho about clean aid, in caves or out of them. I heard that Fixe bought the rights to the old CCH alien design and are going to start selling them in the states this October. These are great units that you haven't been able to buy for some years now. Save your pennies. The BD C3's or Metolius' 3 cam units are both good as well.
And as far as hooks go you'll need an assortment of them as well in a variety of shapes. Get some cam hooks. You won't be sorry.
And as far as limestone breaking under the hooks, that can happen. The good thing about sandstone is you can just about file a divot with the point of a hook to set it in!
I think the best way to practice is to get a weekday off and head down to the Red with a climbing partner and more trad gear than you think you'll ever need and get on some clean, moderate, lines with good protection. That way to won't be spending hours on a classic when there's a line of climbers waiting to get on. Pick something you could free climb out of if you needed to, so long as you are comfortable free climbing and placing protection. If you aren't, aid climbing is actually a great way to learn to use and
trust the gear. A few routes that come to mind that are 5.10 or below (I think I remember most of the locations, but don't quote me)
Rock Wars (hands and fingers)/ Long Wall
Headstone Surfer(hands)/Funk Rock City
Cruising Lane (hands and fingers) / Funk Rock City
Rite of Passage (hands)/ Funk Rock City
Brontasaurus (hands) / Pebble Beach
Andromeda Strain (hands/thin hands) / Roadside Crag
Father and Son (fingers) / Lady Slipper
The Return of Geoff Beene (fingers) / Wester Sky Bridge Ridge
There are TONS more at or below 5.10 and even more once you get up past 5.10 free, but these are ones I've done, can suggest and think would also be good to learn aid on because of their consistent natures. Obviously because they are established free climbs and all of them classic lines ABSOLUTELY NO DRILLING or modifying holds WHATSOEVER. Period. Otherwise you will have some seriously pissed off climbers commin' for ya! But really, you won't have any trouble getting good solid, whipper worthy gear in all of these lines. I'm pretty sure they all have bolted anchors at the top as well, except Andromeda strain which has a tree.
Anyway like I said try not to practice aid on these on a weekend because people waiting to free climb them will give you the stink eye. However, you can also aid climb in the rain and/or winter when the population of the Red drops drastically with a lot more impunity.