Well, it is an emulsion lift, so the actual emulsion will exactly match the size of your print.....the white border usually shrivels, as you now know, so it's even smaller.
However, it
is quite possible to stretch the emulsion and make your final image somewhat larger. But that takes a lot of practice or you'll just end up with a lot of extra holes from tearing the emulsion. I dunno, sometimes when I am working with it, it seems the most fragile thing in the world, then sometimes I am impressed that it holds up as well as it does under my handling.
The longer you keep it under the water, the more friable it becomes - BUT, that's also the best way to stretch it. I've learned to omit the use of the mylar and just slip the watercolor paper right in the receiving tray. That gives me more time to manipulate the emulsion right on the surface I want it on.
Here's one I did a while back while experimenting with deliberate tearing of the emulsion sides, in an effort to make the entire image seem larger on the paper. It's not my fave, but I did obtain the desired effect. I'm posting this as an example of how to make your smaller format seem larger. And note: I trim the white border of the image almost all the time now, so I end up with even LESS emulsion. For something like this end result, I thought that bluish/purple outline the border leaves, while so nice on some lifts, would only be a distraction here. Apologize in advance for the crappy scanning.

I was thinking exactly what you are: I don't want to be limited by "faux" borders or edges, so I went a bit wild. Do you think this technique might be useful for you too?