You need a few things. Minimum of 120cf back gas, 30cf deco bottle, 3 gas computer. Not something to just do. All diving is solo, so you need to be confident and self sufficient.
This week has turned south on me also. Spent all day yesterday buying a car, working wens thurs, and taking out charter divers fri and sat. Week after looks better tho.
My experience is limited to free diving in freshwater with sling spears. As for fish, i would be interested in catching anything bigger then your typical schooly, i mean bigger is always better and the snapper down there look like alot of fun. I grew up fly fishing in rivers and ive always wanted to spear fish and figured if im in key west i should probably look into it.