A gun is a gun, so...

Try this;

Tighten both of them dead tight.

Shoot 4 3-shot groups.

Then leave the front dead tight and LOOSEN the rear 1/8 turn.

Shoot 4 3-shot groups.

Leaving the front dead tight, loosen the rear 1/8 turn more.

Shoot 4 3-shot groups.

This can be done easily at the range and will likely tell you alot about the guns accuracy and where to tighten the gs's.

What you seem to be describing, a truly loose front screw, is never conducive to good accuracy.