Plant out and let grow for a few years before trying to manipulate structure.

Thanks!

I don't have a good site for them yet. I plan to put them in bigger pots. Do you think they will be ok for a while (maybe even another year)?

Here is a link that might be useful: I have pictures...

Results depend on how big the bigger pots are and other details of the care they receive for the next year.

Natalie, did you root some branches, or did you take some sprouts at the base of the trunk? If the latter, you will be disappointed. You may have starts from the rootstock which is probably a different plum and not near as good.
Mike

That is a good point! I checked with my inlaw and luckily their tree is not grafted - they got the cutting from a friend and simply put it in the ground. The prunes from last year were super sweet. So looking forward to it.

Looks like you are good to go!
Mike