Question about how to calculate a Companion's half-share. There are 4 PCs, each of them has a Companion (8 total people), and the party obtains 800sp worth of loot. Would each Companion get 50sp (1/2 of 1/8 of the total loot as split 8 ways), and the PCs split the remaining 600sp? 

The way I do it is this:

Add up all the shares. In this case, 4 shares from the full-shares belonging to players, and 2 shares from the 4 halves from the companions. This means 6 shares. 

Then, divide the total by 6. This gives you the value of a full share (i.e. the amount each PC gets) and halving that amount for each companion. 

800/6 = 133 (with a coin left over)
133/2 = 66 (with a coin left over)

So, each PC walks away with with 133, each companion 66, and there's a few spare coins which I usually handwave away as getting lost behind the back of the sofa or whatever.