Well well........ that is an odd duck.
It doesn’t look like the idle well is drilled at all....... at least, not from the top.

IMO, anything “oddly” done(compared to “normal” performance metering blocks), was to address something emissions related.

For what you’re doing........ I’d def be experimenting with a more traditional and user friendly metering block.

Edit:
There’s a lot of good info in that link Mattax posted.

However........ I don’t see how all those mods would put you further ahead than just using a more tradition block.

I see in the specs for the original block that the ifr in the idle tube was .022”.
That’s not going to work at all in a Stocker build.

I’d also be very careful examining both the primary and secondary idle feed circuits, since there was a mention in the link of the primary idle curcuit interacting with the secondary side.
I would insure those were isolated from each other.