> which would be best
Whichever is cheaper for you.
I don't have the specs handy, but the 1N100x series is all the same except the maximum voltage ranges from 50V to 400V. In this case the 50V rated 1001 is plenty. And back 25 years ago, the 1N1001 was cheaper than 1007. Now the 1007 is just a few cents, so the 1001 isn't any cheaper when you buy just one. And many of us stock-up on 1004 or 1007, even if most of our needs are low-voltage and the 1001 would work.
So if you have to buy one, just one, if 1001 is cheaper then buy that. If you have anything like 1005 already, use that. If you plan to do a lot of DIY and don't have a bag of generic rectifers, buy a 10-pack or 50-pack of 1006 or 1007 which will cover all lower-number 1N100x applications, and the quantity discount is large enough to justify buying rectifiers "too good" for many uses.