how does it run? did you do the mods, or did it come to you like that? If you just added the mods, I would go two full sizes (stock jets) up, if it were me.
Then once it idles ok, stab the throttle, if it pops, or hesitates, go up one on the pilot. if you get a dead spot midway through rpm, change needle position.
have a look at the spark plug of course
However, this carburetion knowledge is based on 660's and lawnmowers..350 not so much.