1966 Canadian Dollar Small Bead?

It is not small beads because the A is just to the left of the bead.Press ctrl and click your mouse for a larger scan.

There was a good discussion on this topic a few years ago:

https://goccf.com/t/56736

For the large beads variety, the "I" is to the right of the bead and the "A" lines up with the bead.
For the small beads variety, the "I" lines up with the bead and the "A" is to the left of the bead

with Shafta; this one is easy to spot w/o counting beads.
I have posted a closeup of a certified SB on the link provide above.

AFAIK there is no 1966 MB (medium bead). But, the identification of SB MB and LB is from the 1965 run.

1965 was the first year of the new more mature Queen portrait. It started with small beads (SB). The 1965 MB was the intermediate single-die test of the modified portrait to help the dies last longer that was then employed as the LB the rest of the year. And the LB was used in the entire 1966 business strike production.

The 1966 SB is a mule of the PL production, and was rejected. But, somehow a few hundred leaked out. Some call it a backdoor job.