My boat is 2006 direct drive wake boat by Sanger. I use it for skiing, some, wake boarding, less in recent years, foiling, most often, and surfing.
The first thing you need is a very low pitch prop. If you surf you need to get the RPM up so you have high torque when only travelling 12 MPH. Mine with a 1:1 drive has an 11" pitch but a 10.5" would also ve fine. I only lost 1 MPH top speed going from a 12.5" stock prop to the 11 as inboards hull speed out, unlike a boat you can trim up high.
First weight bag you need is in the ski locker. put the biggest you can in there. Next would be one or two big bags in the rear. If you can fill the space to seat height behind the engine box you are left with a good lounge area. The more weight you have, the bigger the wake. (and the more likely you are to swamp the nose or have wake slop over the transom.
I'd recommend getting a wake shaper that stick on the side of the hull to get the best surf wake. I use a Nautical brand but others also are good.
An adjustable trim tap is a help, like a Bennet surf tab but that is starting to change your hull. You probably have a flat fixed plate now. That's great for skiing and fast starts but it stops the stern from sinking as much which makes it harder to get the right shape for wake sports.
I will not give up the handling of my D-drive so I've played a lot with different things to keep my kids (now in there 20s) happy with their sports.
