Been watching the thread but as I have no personal experience with this type blind I can't comment - directly. I do have a bit of experience with geese though. As for the size, We used to use four to six foot silhouettes mixed with the regular blocks with good success. The birds didn't seem to notice but I do believe they could spot them farther out and it helped to pull flocks that would otherwise pass by. When laying out in the stubble I have hid between two of these large decoys with fair success. I agree that high vegetation is bad in goose hunting. They tend to stay well away from anything they can't see over, at least fifty yards. Pits are certainly the best cover and most comfortable. Today's hunting of resident birds requires mobility though. Those residents are tougher to fool as well. They're here year-round and seem to know every wrinkle in the landscape. A close friend (who's also a guide) uses the big flip-up decoys you hide the upper half of your body under with excellent results. A good closed cell foam pad to lay on and a back rest is a must though. Finally, I feel good camo is your best advantage no matter what else is used. Keep it simple and realistic. Natural vegetation is best but anything that MATCHES the immediate surroundings will be better than generic patterns.
Good luck!