Ok so I kinda have some good news... I found a video of the fuel circuit on a 2245 and the mechanic mentions that the 2210 is similar so I think this is a definite step towards progress!

Here's the link: https://www.carburetor-blog.com/knowledge-base/holley-2245-pump/

I've been searching for a needle for a 2210 and nothing so maybe searching for a 2245 might work! At the very least I have the dimensions of the check weight now!!

The more research I do the more I keep finding posts of people running into the same situation of a missing needle valve... I wonder why so many similar/same carbs are missing the check weight?