I tried a Honesuki and it didn't work as well for me. The Hankotsu may be a better choice for boning, or a good carbon boning knife that you can touch up easily on a steel. For trimming fat, I was using a few different 210 Artifex and 240mm Artifex and Addict 2 gyuto's, but a good 150mm or 180mm petty would also work for trimming the fat and silverskin and be more nimble, but wouldn't be as good for the actual boning since they tend to have thin edges. The Hankotsu should be able to do the boning and trimming; maybe get 2 so if it starts to lose it's edge, you can just switch to the other one.
This Hankotsu should be good and got good reviews, but it's pretty pricey. http://www.chefknivestogo.com/kielcaha15.html
The Hiromoto AS or G3 150mm petty, Fujiwara SS or Carbon 150mm petty, Artifex 150mm, Tetsuhiro 150mm petty, etc should all work well for trimming duties if you want to use a petty.
For slicing down roasts and portioning stuff, I go with a 240mm gyuto or a 270mm suji. I also have used a Tojiro DP 330mm gyuto for slicing roasts, too. 1 cut and you are thru the whole roast