@kanada01
This sounds like it is likely more of a template build question (over in the professions thread) now.
In short if you have the right build (skills / stats / suit) then you won't really run out of mana from spamming AI. I'd recommend using the SSI calculator that can be found on UOGuide (and I think the UO Forums has one). This will be how you can figure out what your stam/SSI combo will be to swing at the max speed (1.25s).
For my sampire I have all the required SSI (based on my stam of 190) on my suit so that I can use a bladed staff & double axe without adding SSI to the weapon. General rule of thumb is if you are able to do 100+ damage per hit (based on several factors) then you basically will leech enough mana to make up for whatever you are using. That said, you can use a broadsword (or war axe) without SSI to maximize Mana leech as an option as long as you have the proper stam/SSI combo for your suit. If you are using macing I'd also suggest a black staff for using whirlwind which is a sure fire way to top off your mana (as long as you are hitting several targets).
Sorry this isn't a nailed down blueprint of what to do but you will find that there is no single correct way to go about the build. There are several general guidelines (again would suggest the warrior profession section) to help you work towards your end goal but one of the good (and bad) things about UO is that there are several options to get to the same point because there are a lot of dependents that you need to consider (budget vs suit / time / what you are fighting / template / group vs solo / etc) .