I'm pretty sure the SEPP rules require you to use the current or prior month's rates relative to when you actually start the SEPP. So keep in mind that it can change. The IRS publishes the rates monthly here:
Somehow they've already published February 2020 rates here:
which shows a rate of 2.1% for 120% of the mid-term rate assuming annual compounding.
Note that you can also pick a lower interest rate if you want; 2.1% is the highest you could go. You can also carve your IRA into two pieces and do an SEPP on only one of them; this is helpful if the calculated withdrawal is too high for your purposes.
"At times the world can seem an unfriendly and sinister place, but believe us when we say there is much more good in it than bad. All you have to do is look hard enough, and what might seem to be a series of unfortunate events, may in fact be the first steps of a journey." Violet Baudelaire.