This can vary widely, and, of course, from Sagas to sagas. Some will require you to do research, some won't at all.
I like the idea that some new guidelines require more or less work, but, IMO, this shouldn't require much.
For exemple, since the MuCo guideline to give a minor ability already exists, 5 points could be enough to create a guideline to grants a major ability.
OTOH, if you didn't have that basis, this could require 5 more points.
I like the idea of Bonisagi experimenting on spells randomly, with "discovery" results sometimes granting, among other things, a result that use a "new" guideline (and an insight), which prompts the boni to research and integrate this in hermetic magic.
This means that, in-game, researchers have an incentive to do both random and controlled experimentation.
But that's just me.
I did a (verbose and badly edited) post about this some time ago. Never had the time to go back to it, but here it is: