I did Ambon thru Banda Sea to Missol Nov 2015. It was a great trip. Yes as Mike V. wrote Hammer season is best Sept- Nov. Guests on the boat and dive guides and cruise directors all confirmed this.
We did our trip a little differently than some Ambon-Sorong crossing trips, we didn't dive the spice island with the fort nor visit it. We dove for Hammers of another couple of small islands Kekeh Besar I believe.
We would did a couple of days there doing 3 dives a day. We would start by diving down the reef a bit then head out into the blue hoping for a sighting, stay out in the blue for a while then head back to the reef. The first 2 dives of the day would produce a few in the blue and sometimes a few on the reef. The 3rd dive of the day was done late but before sundown. That was the most productive time of day and when we would see big packs.
It was a great dive trip with really good other dives in the Banda Sea. We had glassy sea conditions the crew had never seen before, lots of dolphin spotting and a few whales also. Cruising up to Manuk in the morning as the sun is rising and then watching all the sea birds circle and take off for the day was really spectacular. Then finishing off the trip with some time diving Misool area was the cherry on top of the sunday. ( I must say I spoiled myself and then did another complete RA LOB, to spoil myself completely.)
The ROF trip looks awesome Dan I really would love to do that trip as I dream of seeing Komba erupting as I surface from a night dive.