I would wait for the actual 1099-R to arrive in 2020. There is no advantage to amend prior to that just in case that the amounts on the actual 1099-R are different from what you think they will be. You have 3 years from today (Apr 15) to amend 2018.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
