I finished my Tower Hamlets regiment for Parliament this past weekend and the Romanov's work out well. The couple of S&S figures and a few S&S head swaps are hardly noticeable though the S&S are a millimeter or two smaller. I looked at some reenactor pics (Col. Charles Gerard's Regiment of Foot) and differences in individual soldier heights is noticeable so I now officially chalk up differences in the two figure lines to that from now on. Poses of the Romanovs vary less (the arms torsos/legs you get in the bag of 5 are all the same...heads vary) than a bag of S&S so I think you need the S&S to get a good range of poses in a unit.
I was also able to change out my Haselrige's Horse flag thanks to tidders at "For Ye Kinge"...many thanks Alan!