I had a Miyata from that gendre and did my first brevet back then. The 310 from memory had good geometry and adequate plumbing. Ride it for a year or two and upgrade to maybe a Lemond 853

Your gearing is fine. I generally use a 46 tooth big ring unless I am serious and then it is a 53. We have a very fast Rando in PA who uses a 42 tooth in the front.

I'm a EE. Shutter Precision is what I would have bought with my budget if I was satisfied with the lamps overall. I use batteries. I will someday go to generator

I mostly ride FLO 30 wheels, Zipp 404, or Shimano C50. No problems mostly. My front wheel has 20 spokes. My rear is 21, 24, or 28 spoke and I am not a light weight. Wheels are never sunk costs...I would consider a set of aero wheels if I were you