You don't need to leave it for a few days or a day or any time at all. Steel doesn't "creep". It will spring back to whatever it's gonna spring back to right away.

It may be just that these stays are a bit stiffer than the other ones you tried. So just need to go a bit further. If it moved 1mm then you're in the ball park.

Keep going 10mm at a time. So 150, then try 160, etc. Or 5mm increments if you like. Crank it out then crank it straight back right away and measure it. Wear safety glasses. If you get freaked out then stop a bit short. You can just squeeze the wheel in anyway. I doubt the bridge tubes will pop out as they're quite far away. The stays should bend first.

A top tip from Paul Brodie's videos is actually to go 1mm more than you need. This makes it easier to get the wheel in. It really works. So in that case you'd go to 127.