I live VERY close to Weeki Wachee and have dove it once. In my opinion it is not worth $50.00 to do this dive. It is not very deep and there is very little to see except maybe a turtle (striped leg)swimming out of your way.
I have never dove Hudson Grotto but it is considered by most, to be an advanced dive. Low visibility in the tanic water make it difficult to keep buddy teams together.
The other suggestions are much better........Devils Den, Blue Grotto, Manatee Springs, Hospital Hole, Crystal River with the Manatees etc.
PM me when you get in and I might be back from vacation and be able to show you around a little. Please let me know what you like to see and do when diving. Spearfish, wrecks, freshwater, saltwater, deep, reefs, ornamental fish watch as well as what temps you are prepared to dive.
Gulf water will be in the low 60s, Atlantic water will probably be in the low 70s.