You'll have much fun, i am a bangka fan as well, been there 5 times returning in April at Murex.
Banga is a mix of Wide angle and macro,
best dives sites for me are Sahaung and BatuPendita for wide angle (Sahaung is probably one of my favorite dive sites worldwide), for macro Bangka is pygmy seahorse heaven you'll find lots of Pontohi and Severnsi, mor ethan in Lembeh. Demak is great in that respect, you may fnd as many as 8-10 pygmies in 12-15 meters of water which gives you plenty of time to shoot them. Probably the best muck sites are on themainland coast nerby Likupang, Paradise pier is an outstanding site thta micxes various biotops like a pier, algae fields, typical muck and coral reef. I like as well Batu Tiga which is a pain to decide whether it's a macro (harlequin shrimps, pompom crabs bargibanti pygmies, nnudibranch) or wide angle (big frogfishes, healthy corals, fish schools) dive.
In teh meantime you can click on my Flickr gallery (thais is the link to my Bangka album) to have a taste of what you will see.