I fit an Adept22, RRC2+ two micro switches and two 9 volts in a 2.6" bay, 6" long. Two Stratologgers should be pretty easy. Use the small 1/2" aluminum channel from Lowes and put a piece of G10 on each side of the channel. Batteries on one side, altimeters on the other. Your threaded rod runs through the channel. I've since rebuilt the av bay for that rocket to accommodate one RRC2+ and one lipo. I epoxied the boards directly to the threaded rods and put a screw switch on the edge of the sled where it will sit close to the coupler.
Another option is use tubing in between the two pieces of G10. I just did this to build a bay in the nose cone of a Wildman Sport. It will fit a RRC2+, 9 volt and screw switch.
Lots of options out here outside the box.
I'll get some pictures of them and do a better write up. I hate trying to type on my phone.
So here are some pictures of my double decker boards. They ain't pretty, but they get the job done.
First and second picture is the old sled I was going to use in my level 1 bird. Also my first electronics sled. I decided against full redundancy in lieu of simplicity. 1/2" channel on the ends. It was setup for a single 1/4" rod through the middle and the channel was tapped and attached to the lids via #6 screws. This turned out to be a real PITA to get everything assembled. It worked with only one lid attached to the sled, to keep it from spinning on the rod, but still. The micro switches in the middle are both closed when the screw is tightened. I never flew this setup but I have a similar homemade screw switch (one switch) setup in my Cowabunga and it works great, hung on a power line all night and was still beeping the next day until I got there to turn it off. Only thing is both altimeters turn on at once. Then you have to discern all the beeps at the same time. The other side is bare now but was setup for the Adept and the RRC2+ (all I had at the time). So it will easily hold 2 Stratologgers.
Third picture is what the first two evolved into. The flip side of the board has a place for a LiPo and Jolly Logic Altimeter 3. The charge canister is a piece of blowgun attached with a piece of #10 threaded rod and JB Weld. I recently had one come loose so I have moved onto something else. The resistors are there just in case the ematches short so the LiPo wont fry my RRC2+. I have a 6 position connector epoxied to the board for quick connect/disconnect. All of my boards were going to have this setup, along with a "daughter" board with the idea being less tightening and loosening of the screws in the terminal and less removing the altimeter from the board; but now I have more altimeters than I have rockets that need them. This one has a MissileWorks screw switch epoxied in between the two boards and is nearly up against the side of the coupler so it is real easy to find
Last picture is the board for my Wildman Sport nose cone, no wires yet. This is the 9 volt side, the other side is only 2 standoffs for a RRC2+ so no reason to post that. The metal thing flopped on there is a piece of aluminum that keeps the 9 volt from running off. I have two pieces of tubing running through the board and the G10 is epoxied to those. My nose cone has 2 #10 thread rods epoxied into it. This slides right down into it. Before it housed 4 oz of weight, this bay will weigh around 6 oz so I should be spot on for stability for baby H's. I ditched the blowgun in exchange for a .308 casing, cut off right behind the neck. It will hold 1 gram plus the ematch and some dog barf. 357 Magnum proved a big on the small side, as did 45 ACP.
Like I say, not pretty, but maybe you can get an idea.
Mikey D