When I foil the ribs, I usually put them meat side down & you can see the liquid that is built up under the membrane.
I have even done 2 racks with membrane on & membrane off. The membrane on was juicier.
Judy, my wife told me from now on always leave the membrane on and she is my worst critic.
Looking forward to hearing how yours turn out.
One last note, you need a thermapen or one like it with a thin probe that measures the temp right at the tip.
I've tried a Maverick & it doesn't work. The readings are inconsistent.