There are so many points here worth understanding and supporting. The main one, to me, is anyone trying to emulate Jerry's exact rig who's not playing at stage volumes like he did is, ultimately, chasing after wind. Better to seek his sound than his gear and that will often mean deliberately not
seeking after all of the exact same components he used. Myself, this took me quite a while to accept but as a result I've been playing more and chasing less.
Regarding a plexi shield for a combo, personally, I own one of thesen by Clearsonic but honestly, I don't use it (I don't like the overall tone impact):
On building compression into an overdrive pedal directly, the Visual Sounds Route 66 pedal is 2 pedals in one but the concept is similar:
On standing as close to your speakers as Jerry, no thanks, I subject my ears to enough stress already without deliberately doing this.
"For me, I think the only danger is being too much in love with guitar playing. The music is the most important thing, and the guitar is only the instrument." Jerry Garcia