SPA rear sights windage adjustment

[Ultramarine]

Can't understand the way rear sights can be adjusted on SPA rifles
Loving pumpers, I bought an Artemis LR700W some months ago and I'm slowly getting used to it. I didn't put any scope on it and I use  the iron sights as they're good looking and efficient.
But I'm just puzzled by the way the rear sight works concerning windage: two opposite screws that, once more or less screwed keep the notch blade in place. But adjusting it is a PITA, as I couldn't guess till now how the screws influence its position - or not.
Any advice ? I disassembled it but this didn't help me.
If I'm not wrong, all SPA's PCP and CO2 rifles have the same rear sight, as well as the Diana Stormrider and the Seneca Dragonfly.

[bandg]

If they have two opposite screws then they probably sandwich the blade between them.  To move blade(impact) to left, slightly loosen left screw then screw in right screw until snug again.  It isn't always the easiest method to adjust but I've had a few like that and they can work fine.

[Ultramarine]

First of all thanks for the info.
When I disassembled the sight, I couldn't see anything that could be "sandwiched" between the screws but I noticed the kind of tunnel/bore in both side of which the screws were inserted had not the same diameter all along its length, one side being way larger than the other . I just can't imagine of what use that difference can be but once the screws tightened, even partially, the notch blade can't move.
So I'll try your method tomorow (now it's night time in France...)