Chris Doerr and his wife Annika are great guides. They also have good gear. Chris is on 808-264-1830.
I've been diving with them several times, highly recommended.
Scuba Barry is another idea.
info@scubabarry.com. He has a website. This may be one of the only places to rent tanks on the West Side, most dive shops were destroyed in the fire.
Best West side sites in the winter will be Olowalu, and Wahikuli. Olowalu is probably one of the best sites on the entire island. It has no northern exposure, so it's a good winter dive. Very few people dive it unless conditions are **** everywhere else. It's a navigation dive, so a lot of people don't feel capable. It's about the most beautiful reef on the island. There are several entries for Wahikuli, this is a great place to see turtles, and most people don't dive there either.
Coral Garden by the Pali is also quite good.
Mala Pier is the classic W. Maui site, but it's probably gonna be problematic since that's the only West Side boat harbor now.
Maui Dreams goes out from Maaalea Harbor, they are under new management now, but I think they could be a good option, if you want to work w a dive shop/small boat.
If you go to Lanai and can put group together, you should try to contact Kristine Belew, she runs a charter catamaran for the hotel it's kind of expensive but if you get a group together maybe affordable. You will get a private tour of the Cathedrals, which is really unique and quite beautiful.
If you want to contact me with questions feel free. I'm often out there in the winter and might be up for leading an Olowalu dive.