Pumpin pals flanges?

Can anyone give their feedback on these?

I go back to work in Monday and currently use 21 mm flange in my spectra pump. I get decent output, but can’t help but wonder if I could get more. The flange might be slightly big but not big enough to go down a size.

All the reviews I have read seem to be from mommas who had blisters or other discomfort while pumping. I get some mild discomfort but generally don’t find it uncomfortable.

Can anyone provide feedback on how it worked/effect on production when fit or discomfort wasn’t an issue? Looking at it, I’d have to buy an adaptor for my spectra pump and the Medela valve. Plus more Medela bottles so I’m looking for reviews before making that investment (and returning the spare spectra parts I ordered).

Thanks!