So still no response on how large the largest n-th they will throw at us?
Well, we don't know ourselves...
When we try to make our own things, for testing purposes, we are, too, limited by the machine's BASIC limits. But our (critor's) algorithm is valid for any input.
We have not coded anything for the z80 but e do know there are limits....
Just try to make something good enough for "relatively large" numbers (even though some small nmuerbs already take time to compute, so...)