No need to get fancy with any of it. Most bolts will clear the timing sets I use (mainly Cloyes). Before Doug at POP started offering bolts, I would just buy a high quantity of 7/16-14 x 3/4 bolts from McMaster/Fastenal or use the ones that come in the Durabond engine finishing kits, then cut them down to 5/8". Never had a problem. Doug's bolts are made by ARP for T&D and they're already the right length, so I just have Doug send me a hand-full every now and again.
Not a fan of reusing the factory ones. By the time I get them, they've been removed/installed 17 times and look like someone with a small screwdriver and channel locks tried to get them out. I use mainly steel thrust plates, cam gears, and cams, so the new fastener "looks" correct.
An unplated 7/16-14 Grade 5 fastener torques at 50-55 according to the charts and I'd rather not rely on threadlocker to hold it all in there, I'd rather stretch that bolt accordingly. I personally just don't like the feel of trying to torque something with a Phillips (or PosiDrv) head.