My group is fully on-board with the notion of hiring henchmen - and lots of them: we have a paladin with CHA 18.
But after a few dungeon adventures with such a large group (10-12), they have mixed feelings about the experience. They like the extra offensive power and the extra bags of HP, but it does slow things down (esp. with initiative).
So now they want to use the henchmen for something else. They're party level 4 and they've bought some mercantile goods while on a journey. They weren't able to sell them on the way home, and they are also short on cash, so they know they need to get into a dungeon to get some phat loot.
They want to go into the dungeon (the 6 of them plus some select henchmen), while sending the other henchmen to another city to stay there until they sell the mercantile goods. I am fine with this, provided they get paid and probably with a morale roll each month they are away from their boss. I'm not interested in punishing them by having the henchmen get robbed or killed (or at least making it a very small chance).
Here's my questions: do your parties do this also? How do you handle it? And who gets the mercantile XP? Just the henchmen present? The party?
In situations like this, my default is to give the mercantile XP to the party, less the henchman’s share (that is, giving the henchman their normal half-share).
The PCs put up the gold, after all, and are the ones assuming the mercantile risk, so they should definitely earn XP of some kind. However, they are not assuming the adventuring risk, so it should be less XP than if they had done it themselves.
I haven't done this before, but it sounds totally reasonable. It can take time to build up a good stable of henchman, and you never know when a bunch are going to die, so best to keep more than you need and not bring some.
Those that you don't bring will only need their monthly wage. They won't get a share but also won't get XP. By the same token, if you send henchman on mercantile ventures, only they get the XP for it. A mercantile venture is a distinct activity from being a wealthy trade captain who has many caravans and ships going to lots of different cities on their behalf.
Haven't done it; sounds cool and totally would; per page 146, only the characters going on the venture get the xp. The profit split is an in-character matter between the PCs and henches but doesn't change the xp split.