Agree that a Gillette adjustable on 1 is probably mildest, then the Krona, then the Tech without the D-shaped holes, then the black tip SS, then the black-handled SS, then a blue tip. (The last three are pretty similar.)
Wilkinson Classic (made by Treet). Way milder than a Tech and one can doubt if it has any use at all but there it is; the mildest razor I ever came across.
This piece of junk no-name vintage razor is the most mild
After that, the Tech's with the straight holes in the base plate, then a Krona, then the Techs with the triangle holes. The adjustables can be set to a mild number, but their heft still encourages the razor to be more aggressive than the Techs. For the same reason, the aluminum handle Techs feels more mild to me than the other Techs.