Well that is not what I was thinking of.
I thought if two ways while I was working.
One would be to NOT drill all of those pesky holes.
Get a 10-24 tap drill holes in the fittings and thread them then use the 10-24 screws as set screws.
Two in each fitting.
An 8-32 screw might even be better or thumb screws.
Instead of a 90 at the top use a Tee.
This way you could have a long stick of PVC and just slide the Tee up and down.
You could even use a hose clamp if you wanted to.
Not to insult but if you or anyone else doesn't understand I can draw a picture.
I cannot express too much how everyone needs to have a screw pitch gauge.
I keep one in my pocket like a knife.
Worth