I have also been experimenting with s/h and now have 5 in it - a struggling onc (was struggling before s/h and now doing really well considering is state before), a paph pinocchio (didn't even bat an eye at the change) and the rest are phals. The phals all had a couple existing roots go bad with the change but have all the responded with new root growth. I would however have a good root-growing fertilizer on hand to boost the new root growth and help the adjustment.

As far as the water in the bottom is concerned, I am on the other end of the spectrum - mine never go dry (not so much because I always fill them, but the weather just isn't that dry). So far no problems. I have been experimenting with having the reservoir outside the pot so that the rocks wick water up but there is no puddle IN the pot. Hard to say on the success of that though since the plants in it were rescues anyway.

I do however make a point of not just topping off the reservoir but completely flushing the pot regularly just as I would with other plants.