1st a caveat, I'm a piss poor skier, usually one of the worst on the dock on any given day. So there is a whole lot of stuff I'm always doing wrong and all sorts of advice to "help" me and as you said, too many things to work on means you really don't work on anything, I've found he best thing is just before I drop off the swim step to announce what I'm working on for this pass. Such as, "I want to make sure I let the ski finish and I don't close off to the boat when I'm behind the wakes". This gives those who are in the coaching seat a specific aspect to look and and offer insight to. In the event they want to give advice on other parts of your skiing you can simply direct them back to the topic of the day, or let them give you tips on other parts of the run and table the initial area you wanted to work on to another set.
It gives you control.
This approach has also enabled me, the local hack, to help the better skiers. I might not be able to look a full pass and give constructive criticism, but I can easily tell one of the -38 guys where they are hooking up off the ball or what kind of angle they are generating on the off side vs their onside.
YMMV.