What is your primary source of Gyrda Pads?

I exclusively use Mk3 for Electriums, Zinbiddles and Impulse detector and Gyrda keypads.

Agree with Rius. But for more clarity, I bulk up on r8s and r9s since they come in more slowly, then when I have a large bunch of those, I move on to mainly Electrium. Passive income of Zinbiddles isn't enough, but it far more closely matches need than Electrium income. Thus I tend to let ZBs slide most of the time, bank more than I think I need of r9 and r8 (since you never know how much you're going to need until they announce a new requirement and you don't want to be stuck needing something that comes in so slowly), and the rest is focussed on the r6 mats.