I used stacking type corners on the top of the main case and the bottom of the pedal bar case, then used a small butterfly latch on each end to hold the pedal bar case in place on the main case. This makes a single unit when you're using the wheels, but it detaches quickly and easily for loading and unloading, or setting up.
The guitar fits the case snugly and is surrounded by 1" foam (2" on the wheel end) covered with crushed velvet. The body is supported front and back in the center of the case, and also at the changer end. It does not sit on the tuning keys and changer. I put foam blocks in the lid to contact the end plates on both ends to keep the guitar tight in the case. This guitar ain't gonna move around in the case when it is handles in a sane manner.
The pedal bar case has foam in the lid to put pressure on the pedal bar and legs (in a leg bag of course), to keep them from moving around.
As you know, these old MSA's are pretty heavy, the main case with the guitar weighs 70 lbs, and empty, it weighs 28 lbs. The pedal bar case weighs 31 lbs. loaded, and 18 lbs. empty.
The materials probably cost me around $400, and I spent about 6 weeks in my limited spare time making them, but I am very pleased with the results. The snap-together design may be something some of you other players and case makers may want to take a look at.
Here's a bunch of pictures.
on it. I updated a few things too, like making the knee lever angle adjustable, and using my shaft stop design. I also put adjustable springs on the E9th neck to try them out, and they work great, so I'll be installing them on the C6th in the next week or so. I also had to raise it up 2". I am surprised at how good it plays and sounds, if it had been a dog, I sure would'nt have spent the time building the cases. 
