Okay, nevermind, just shot myself in a mirror with an awkward hand position.
Canon E1 hand-strap + Optech Pro-Loop strap used together:
The pro-loop connector is flexible, so I managed to insert the E1 grip at the battery grip area so that the grip strap loops around both the grip metal and the pro-loop strap. However, whenever I used the hand strap (which is everytime I pick the camera up), the pro-loop strap will be forced into the grip, so it kinda splits up after awhile. That's why I have masking tape to hold it in place.
You can see my lightsphere in the reflections. Cool haha..