To all you experiece modders out there!

WOuld like to know how you guys built your shrouds over the apex. @ main questions that i would need your opinion or solutions on
1) How do you lock the outer PVC of alluminium barrel on the marker barrel? Screw it on? I wanna try yo avoid scratching the JJ ceramics if possible.

2) How do you make the lever that adjust the ramp on the apex. With the shroud on and a slid cut into it aligned with the slider, i am still unable to move the slider back and forth as its still too short.

Suggestions and pictures guys.