Brent, just curious why you prefer one timing set over another based on cast or steel cam cores? As for dampers, I had a SFI Powerbond on my old 331 SB Ford, my new 347 has an aluminum ATI, and my 427 & 428 FEs used a steel ATI, never had any issues with any of them, other than the minor timing mark crank pulley tweaks needed with the FE ATI unit, (which took all of about 10 minutes to address both). For the money, hard to beat the Powerbonds.
As far as automatic flexplates, back when I ran automatics in my Fairmont, 20+ years ago, I used nothing but factory original Ford 428 C6 flexplates, never had an issue, even with several hundred WOT transbrake launches. I assume, technically the "spoked" 428 flexplates are weaker than solid 390 style, but I never hurt one. If you have a good condition factory Ford flexplate, with nice starter teeth,I would use that, if the engine retains the factory external balance configuration.