I'm all for innovation, Aaron! But, what if you tune your Auber, with your setup on the top shelf, and then you can't use it there? The advantage the wall-mount probe has is more than just "being in the same place" (although this is a BIG advantage!).
The wall probe has a nylon casing/mount. Why? ...heat sink effect of metal-metal. If a metal-based probe is mounted to metal, you will get a heat sink effect from the mounting surface. This is from Auber, and why they use insulating nylon.
What's the big deal about being in one place? Absolute consistency! When that probe, literally,
never moves, the tuning will stay dead-on consistent, every time! Your setup will probably be close, should you change shelf positions, but it
will change...trust me. I spent a lot of time playing with different drop-in probe placement, and became frustrated beyond belief! And, it's why I'm such a strong advocate of the wall-mount probe. Drilling a 5/16" hole, in the back of the smoker, is no big deal, either; the probe fills the hole!
As far as cleaning.... I actually never really "clean" my box probe, like I do the meat probe, and have never had a problem with accuracy. I will wipe it down, with a wet rag, after a smoke, but that's it. Lazy Q....
Probe life? ...Better than the drop-in. First, the probe itself isn't touched or handled. Second, the base of the probe is behind the smoker wall, so absolutely no chance of moisture getting in the probe. Third, the wire is protected in the back of the smoker. Probes are more long-lasting when they can't get wet, or handled!
Don't take this wrong...I'm certainly not "knocking" your solution, but rather pointing out why I believe the wall-mount probe has the advantage, for those considering the options. I have 3 wall mounts, and have never had any issues with them! Well-worth the time, and $, in my opinion.