Hey,
I have been lucky enough to have dived in Bali a few times and I think it is very underrated for what it is, so a great choice indeed especially if you add everything else that Bali has to offer above water.
In terms of macro, as others have mentioned the Tulamben area is the best, Seraya Secrets is my favourite macro site in Tulamben. It does not look like much until you are down there and it's literally one critter after another non stop... Liberty Wreck is a must with ideally a dive at dawn or dusk as you get different light and life.
I would strongly recommend to get your own dive guide if you are serious about your photography (which I can see you are based on your Flickr). They know exactly where the critters are, just tell them what you want to see and they will find it for you. I dive with Liberty Dive Resort which are great, they have guides and a camera room etc and are very well used to photographers. You can also check Matahari Tulamben or go with a private guide check here in Wetpixel/Scubaborad for recommendations.
For the big stuff as you know Nusa Penida is the place. Manta point for mantas and Crystal Bay for mola mola, most dive OPs will do 2 dives in the morning on these sites. The water around nusa penida is 'cold' it can be 26C on the surface but very quickly drop to 18C at 30m and there are lots of thermoclines so 5mm and a hood are a good choice.
If you are into reefs and coral, the reefs around the north of Lembongan and Penida are nice, full of coral, colours and turtles in most dives. Normally a gentle drift but you can stop for pictures unless the current is really strong. Best dive site for me was Toyapakeh, you also have SD, Pura ped, Ceningan wall.
You should have no issues renting a 5mm wetsuit anywhere in Bali, 3mm should also be fine but most OPs stock only 5mm as it covers most of the diving. I also recommend 5mm booties if shore diving around Tulamben.
There are daily transfers between Sanur and Lembongan and different times of the day so you can easily finish your diving in the morning in Lembongan and take a boat to Sanur and then a taxi to your destination in Tulamben so you do not loose a day of diving if you dont want to.
If you choose to stay 'in one place' and not move, Padang Bai could be an option, I think some OPs based there do trips to Penida and Tulamben maybe the guys from the underwatertribe.com can do a tailored trip for you.
Have fun