Transferring Retinues

I've been having a bit of trouble with transferring some of my retinue. My faction leader's about 64 now so I'm trying to salvage them, yet whenever I try and move them they don't go. The target only has one in his retinue. Is it because he's a faction leader or am I missing something else?

Also, what's the limit for retinue characters?

The limit I believe, is 8. To transfer them, you must have both generals in the same army. Then bring up the window with the general and his retinues who you want to transfer, and drag them onto the card (in the bottom, in the army box) of the other general. A little sign should appear now, in the left side of the screen telling you, that the new general have increased his retinues.

Note that certain retinue ancillaries are incompatible with others. For example, a Crooked Judge will never travel in the same retinue as an Honest Man; the Lion will not lie down with the Hunting Dog etc. Also, I'm fairly sure you can't have more than one of the same ancillary in a retinue.

For full details, look in the file export_descr_ancilliaries (in the Data folder of your RTW installation). Find the ancillary you're interested in, and look for a line that starts ExcludedAncillaries. That'll tell with whom (if anyone) that ancillary is incompatible.

I find that having 3 generals in the same army is the best way to move retinues.