Your thinking to much into it ,surf fishing is simple. Get a 6000, fill it with 30# mono, go fishing, it's that simple.
All my spinning reels for the surf are 6000. I put a 150yd spool of 65#braid on first, then I fill it the rest of the way with 30# mono. The braid rarely ever touches the water, so all I'm really fishing with is just the mono, the braid is just backing. I have friends who bought the exact same set ups as mine, but they just have 30# with no braid and their set ups land just as many fish as mine.
The only reason I use braid backing is because I change my mono out 4 or 5 times a year because I fish so much. I always want fresh line between me and the fish. It's easier and cheaper for me to replace a 50yd to 100yd topshot then it is to re-spool the whole reel.