Is it possible to increase the degree of variegation by selecting the most variegated twig from a lightly variegated variety, and then repeating the process?
In other words, I think I've found a seedling with just a touch of variegation in places. Can I selectively graft and so increase the amount of variegation?

I think so, yes. I had a variegated Yuzu seedling and some of its branches felt back to normal green so I took the most variegated twigs for grafting. I think, by selecting the most variegated areas you can get a more variegated form.

Bernhard

I'm hoping to do just that with a Cara Cara. I'm hoping to do through cuttings at first since I have no rootstock.

The easiest way is just to cut all not, or less variegated branches/twigs away ...