I usually re-pot tender/tropical bulbs in May, give it a drink, and pretty much wait for emerging growth before starting regular watering schedule; by then it's certainly warm enough to set pot outside (w/ about 50 others), monitor, and water when necessary. I'm on the Z5 Z6 borderline. I grow Gloriosas, dahlias, Pineapple Lilies, Hymenocallis, Blood Lilies, Lily lilies, Rain Lilies, Tuberose, and other assorted bulbs in containers to allow freedom of placement and then to overwinter in basement w/ ease.
Oft time the bulb or tuber in question will manifest itself when ready to initiate growth for a new season.
You are right to be wary of too much water and no growth for rot conditions might prevail. Bulbs in containers definitely need super drainage, pack some hard Styrofoam pellets/popcorn or rocks in bottom of pots. A little sand in the soil mix doesn't hurt either as it enhances drainage. The premium soil mixes are usually formulated to avoid soil compaction and are conductive to container success, but I still use those pellets (lessens overall weight and facilitates drainage more)..
