[makeitdouble]

To me the key part is really this:

> There's often other work to do

IMO there needs to be somewhat of a give and take situation (which can also work on other angles with pairs that already like each other for whatever reasons).

When finding a balance is just hard, straight rewarding the more knowledgeable/faster half of the pair could work too, provided there is a reliable way to identify them and how much they helped their counterpart.