I would offer a few things for explaining some of this and it more or less explains the path that I take.
The other problem to solve here the choice of resin. 99.9% of the stuff used for bedding a rifle is an adhesive. Its designed to be a glue to bond two pieces of whatever together. Its not really meant to be a mold material. (Why I strongly advocate using a material with a very high percentage of solids that are non ferrous)
-That's all a bedding job really is, a casting of the receiver. My point is when you have interruptions with this casting on a material known to be problematic with adhesion (aluminum) it creates a situation where the potential for erosion/failure is elevated. An easy example would be the stocks that have come through my shop over the years where the pillars have "unglued" themselves and either fall out or push out of the stock with ease. Temperature, shock, compression, and torsion. All of these only serve to aggravate this.
"Zero stress bedding". I understand the intent, but in practice its a bit of an oxymoron. I'll explain.
-The only way you really get to where a casting is "stress free" is by accurately defining the "tool" used to make the mold. By that I mean the receiver needs to be in the condition its going to be in when the thing is all done and ready to shoot. Long story short, make sure your barrel is attached at the correct preload prior to bedding.
Next, guard screws. As I mentioned earlier, good automotive machinists have known for 30-40 years that the fasteners used for things like main caps/cylinder heads, encourages the cylinder bores to distort when they are torqued up. To combat this, they hone the bores with the block preloaded into this condition. Mains are torqued up and torque plates are installed.
Now, take a long hard look at your typical 1.350" dia receiver. The front ring is where the 1st guard screw gets installed. That cross section is approximately .170" thick. On a 28 pitch thread (typically used) that's around 4-3/4 revs of thread engagement. Now, move rearward to the 2nd screw. There we have a little more, right around .220" or so equating to around 6 rotations worth of engagement.
Again, the material surrounding the screw is put into a "wedge" condition where if enough force is applied, the material surrounding it will distort. This can be seen all the time on things where bolts get screwed into stuff with the force of God. The surface immediately surrounding the hole is plasticized into a raised ring. So, go back to the children's book called "The Princess and the Pea." Your action is the Princess. The "pea" is all this distortion being introduced to the receiver body in the assembled state.
If you truly want "zero stress" in your casting, then it works to your advantage to emulate these loads as much as possible during the casting process because that is how the thing will be when it goes together with you behind it at the rifle range.
Sorry if this got too long. Saturday am's and I'm up at 430 most mornings...