ya. you can handle dozens of fish in a 350 gal tank.
How much reading into Saltwater reef keeping have you done?
If you won the lotto or something and can afford it. Just pay your LFS to design and maintain your system. Tell them exactly what you want to accomplish(show them pictures of the kind of aquarium you want to have) and then come let us know what they recommended to you, if they are steering you wrong well let you know.
Gotta set a budget. I did a 125 system w/55 gal sump and all that was needed to get it going for around $2,000 total. That included:
3x250w MH lights and ballasts, dual 72" VHO's, salt, sand,100lbs LR, RO-DI, Scrubbing station, GFO/CArbon reactor and pumps, and a pair of power heads.(But that is thanks to craigslist deals)
Setting up a 350g system with top line gear can cost you tens of thousands easily. Thats why you have to set a budget in mind then you can begin attacking it.
EX: LED lighting for that system would be ideal...but that will run you around $4,500 alone.
Power heads are a must... half dozen Vortec pumps w/controllers and battery backup gonna run around around $3,000. (but thats just drool material. I have to settle for korrellas myself)
Your gonna need about 250-350 lbs of LR thats anywhere from $6-$10 lb.
120-150lbs of live sand should do. A good skimmer for a system that size is in the $500-$800 price range....but you can spend thousands of dollars on a skimmer as well.
I would personally first spend a lot of time researching before rushing into this.
Feeling pressure to go out tomorrow and thinking your gonna get everything you need most likely ending you getting stuff you don't need. Or at the very least...stuff you coulda chosen better on.
Just an example...you dont even knowwhat kind of filtration your 350g tank has, nor do you even know what kind of lights you got on it.Both of those are VERY important to know.
You wouldn't go to a movie theater and tell the ticket seller to "surprise me"...simply because you felt like a movie. You will have already had the research done on what movie you wanted to see.
hope this helps. If you would like to know more, that's what were hear for.