Our Rootstocks orignated from England (M), Russia (B), Poland (P), and new york Geneva. Where you get a young tree doesn't mtter much I think. Those varieties that interest you iterest most of us too. However, there are mysteries with oddball varieties. You may not have enough chill hours to flower reliably, ripening dates might vary a good bit from there, disease resistance might vary lke fireblight, or may not be well documented. LEsser known varieties are more of a gamble. IF there's something you like, try it.
You probably have enough trees to feed the herd already.
The real problem is ordering in october and still wanting the same varieties you ordered 5 months later.......
Even with well known varieties, one site says its for these zones, another site says otherwise, same goes for ripening dates and disease resistance. I read there is atleast 5000 apple varieties.
I got St lawrence by my camp, Cummins about 2 hours west of me, but for some reason I keep buying trees from Kansas. These trees have been photocopied so many times, sometimes there's variences even in a variety. There's 5 different golden delicious strains, thats not including spur or tip bearing differences.
You know someone who grows quality trees, sotres them well, ships them in a good box / mositure, and has a good price, go for it.
I tend to like mom-n-pop places. Their name is on the box. Roots are dug up nicely, branches are damaged ramming it into a box. Bag is carefully wrapped to keep moisture in.