You can see the evolution of the g buy looking a examples of Insular Minuscle and Caroline Minuscule.

Re-reading Gill's Essay on Typography I just found this:

¶Again, take the letter G. The evolution of our modern small g is seen to be chiefly due to the prevalence of & consequent familiarity with hastily scribbled forms (see fig. 3). [below] Nevertheless, in no case does the scribe imagine he is inventing a new form; he is only concerned to make well or ill the form with which he is familiar.
¶By the sixth century a form of writing obviously more natural to penmanship (see British Museum Harl. MS. 1775) had been evolved. And the process continued until all resemblance to the Roman original was hidden (see B. M. Add. MS. 24585).
¶I am not concerned to describe in detail the history of the process in its technical and economic significance. The point that chiefly concerns me is that, with whatever tools or materials or economic circumstance (that is hurry & expense), the artist, the letter-maker, has always thought of himself as making existing forms, & not inventing new ones.

I think just looking at the g in most samples of Carolingian Minuscule will give you a good idea on how to shift between the different g-forms back and forth in history. The more you'll get, anyway, the most complete the picture will be. Gill's example may be misdirecting, since the samples are all redrawn by himself. (Hi, Nathan, anyway! Hope you're OK! )

The evolution of the ampersand from Latin 'et' to & is
equally fun (even if it took fewer steps.)