Q: What is the diameter of the head?
It is .21" or roughly 7/32".
Q: May I know what brand of avex rivets these are?
1601-0410 is an Avex branded rivet.
Q: Are the 1/8 counter sunk 1604-0412 used with the dome head on the puller to create finished dome head rivets? Essentially the A4 rivets that come with the Zenair kits?
No, these are flush head(counter-sunk) rivets. We have no infor if these will form like the Zenair units using the Zenair gun. The Zenair rivets are part numbers, 12-05541, 12-05542, & 12-05540.
