Sorry, I don’t see how a shim (installed after welding + reaming) would sufficiently reinforce that area. Yeah it might dissipate stress from the seatpost rocking back and forth, but the base material is still thin and “compromised” during initial fabrication.
You’re going deep into the engineering side of things but the solutions seem a bit like “half-steps” to overcome some fundamental flaws.
If you’re going to have a tube created for your design, why not go all-the-way? So you don’t have to glue something in? And, to echo Photon, why 34.9mm ST with a 27.2mm post? I’m just not understanding the tradeoffs, etc
I don’t mean to come off like I’m attacking you. Maybe I’m just missing something?