I use the advanced rules but cherry pick, Very seldom have wind strength changes for instance, and use the simple set of ship mats you can see in my AAR's. Just fill them in with a white board marker and return all chits to the bag each move. All ships form line of battle and do not sail as individuals until necessity forces them to do so. ie enemy ship getting in the way.
In this manner I have managed to sail six a side, but would rather not go any higher in numbers.
However, when playing a friend, the inevitable banter makes it much harder to keep an eye on what is happening and exactly where you are.
I think that with practice and developing an order for carrying out each action you can get better at managing larger numbers of ships, but as I said six a side is about my personal limit. You also need to concentrate a lot more if the British are using Carronades.
Rob.