I use online calculators...
The one I usually use didn't work well with 1000 and 2000 dfs
BUT I just found this
I just put used 100,000 and 200,000 dfs.
AND I checked with the percentile point of 1.
I know that as the df goes to infinity that the mean converges to 1.
And it 'worked'.
There's also these tables....
Note that there are F tables if you look on top.