Do not want to get too far off topic but maybe you already have a line that works great in the surf?
Do you have a floating line for the rod already? If so it would makes sense to give it a try in the surf before you get a full sinker. I had used a full sinker quite a bit in the surf but once I really started to understand surf fishing I realized it is more about fishing the currents and using rip tides and such to your advantage rather than cutting right through them and stripping in a sinking line. A sinking line now has became a special occasion line rather than a goto line.
Line control is important in the surf and you have no line control with a full sinker. At best I would reccomend investing in a sinking tip line rather than a full sinker. You give up too much control IMHO by not being able to mend in the surf or reposition your line quickly and easily. If you have a floater already defintely give it a try.
As far as what sinking line for that rod the 350 is best.