I saw this:

Shrinko8 can compress better than Pico-8 itself, so you’re recommended to download the file instead of copy/pasting)

Can we take advantage of this? I haven’t yet tried what happens if you download the cart and then reopen it in Pico-8 editor… are the additional savings still there?

Sure. At the end of the day, if you can get a valid cart/.ROM file <= 1024 bytes, then that means it's under the jam limit. 

Though, if u need this, I'd also suggest adding the .ROM file to the downloads of ur entry's itch page, for completeness (as otherwise, when ppl paste it code, they might mistakebly think u were over the jam limit).

Alas, the savings are only in the file generated by Shrinko. If u open in P8, then save again, it'll use P8's compression routine instead.

Hope this helps and good luck with ur entry! 🤓