These triggers are easy to make very good. All I do is remove the springs for the first and second stage, throw the 2nd stage spring in my box of random springs, move the 1st stage spring to the second stage spot and snip a spring from a ballpoint pen down to about 5 or 6mm long and put that in for the 1st stage. You end up with an extremely light 1st stage that is barely noticeable and are able to dial the overall trigger weight to somewhere a little less than 1lb and have it still bump safe. Takes 5 min to do (or 10min if you have sausage fingers and eyesight like a pig)
Using the OPs air tube method, you could just use the 1st stage spring in the 2nd stage spot and not put anything at all in the 1st stage and you should have a light single stage trigger.
Personally I dont mind having a light 1st stage, I reckon it encourages good trigger technique.
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