XF 1.3 Easiest migration path from SMF

I have an SMF 2.0 board which I am trying to get to XF. No direct converter exists. I've been wrangling with the phpBB converter to establish that midpoint, but the SMF --> phpBB migration has been failing. Could you please comment if you have had success (or failure) migrating via phpBB, myBB, or IPB? I do not have a vBulletin license to use as the midpoint.

The board is 10k users, 250k posts, and 35 gigs of attachments