On another forum there is a discussion on figures bursting through bubbles and other travesties related to blisters. I've been a fan of the AFA custom rails and, despite the issue earlier which was resolved, really think it's a must for higher end and fragile items.
So here's a little shot of them and what they are. If you get anything graded, it's only $25 extra and believe me it's money well spent.
The Uzays are a sliding back open cases with a second pane of acrylic flush with the cardback. Then a square is made to house the bubble.
The Yoda, VCJ, and Leia POCH are custom rails that have a hole in the bottom for the blister stem.
The DSC is a simple acrylic square surrounding a non-stem bubble.