The 18" Stihl Rollomatic E that they came with is a perfectly decent option. Pick your poison as to wether you want to run .325" or 3/8" Picco on it. They pick up a little speed running the 3/8" Picco.
I was going to link to another thread, but now I see that it's yours. I use the rollomatic with 63rm61. And a muffler mod.