Watch the Guitars online guitar lesson by BJ Baartmans from Creative Slide Guidebook
The electric guitars that I use for slide playing are in a regular tuning and have a pretty normal set up. The string gauge is 11 to 52 and the action on it is not too high.
If I want to tune a guitar down or set it up for slide playing in an open tuning, I'll switch to a slightly heavier string gauge like 11's or 12's and set the action of the guitar up a bit of higher. You may have to adjust the intonation of the guitar a bit when using a wound third string. You also may need to set the neck a bit straighter with the truss rod because of the increased string pressure, but that's all easily done.
When I'm using an acoustic guitar, the idea is basically the same: I'll use 12's for regular tuning and 13's for open tunings. With the glass slide and a touch that's as light as possible, I can make it all work like this. It gives me lots of playing options, incorporating regular riffs and chords. For some players, using a higher action and a heavier string gauge is necessary to make it work though. Limiting your possibilities a bit is not a bad thing I'd say. It can all be good, just as long as it sounds right!