Thoughts on seats

[HSSS427]

I have some "original" style bucket seats in my car that are leather on the front, have a removable bottom cushion, and carpet on the backs. Looks like they are made on some combination of fiberglass and wood frames. I'm assuming they are something ERA makes, or has made for them.

The passenger side wooden frame has broken and I'm trying to look at options for new seats for both sides. I've looked at the Kirky web site, and it certainly looks like their vintage seat would work well on the track for holiding you in, but the covers look like they're kind of "cheap" looking if you want something that looks nice as well as being functional.

What did the original SCs have in them and how were they constructed? What's been everyone's experience with different types of seats? What's the best seat for mostly street driving, but 4-5 times a year on the track?
What's the best way to bolt them in? I've just got 4 Grade 8 bolts going through the floor pan with big washers on them. A pain in the azz to hold the bolt head in the cockpit, while tightening the nut underneath. Appreciate any advice.
Thanks!
Scott