Which Tonerider for the middle on my AGM-3?

Long story short - I ordered the AG-1 and a set of Tonerider AC4's, but there was a supply issue so I was offered an AGM-3 in place. I now have the dilemma of choosing which pickup to get as an upgrade for the middle.

I was originally thinking of an AC2 but didn't know if I should get the neck or bridge version. I then thought of the AC5 as an option, but choosing which version to get seemed even harder with the underwound neck and the overwound bridge might make both unsuitable for the middle position. Thinking outside of Toneriders, I was also looking at a Seymour Duncan SH-1 '59 (still with the issue of choosing neck or bridge of course).

However, with all of this, I'm really just guessing without having any real knowledge or experience. Any suggestions or informed commentary would be welcome.

If you want to stick with Toneriders (which is what I would if it was my build) the TR website provides more information on their pickup spec than PBG that would be helpful in making a decision.

Looking quickly, I reckon another AC4 Neck would work just fine in the middle. Are you getting covered or open HB's?

It's not that you can't mix brands, but it can present problems getting a good match if you don't know what to look for technically.