custom seats? race seats for big guy

[RaceDeck]

Hoping someone here will have som information on the options for a custom seat for the track? I am 6"3" and just fit in the stock seat but there is no way with a helmet on. I was even considering buying another stock replacement and having the the cover and padding redone with the high-density foam that is much thinner and would give me the 1' to 1.5" I need. If I could go that route I would most likely use it always and if I ever sell it, I would have the stock one on hand....

Also, the two bolts that go through the firewall behind each seat ( just behind each strap opening on the seat), are they there for the option of seat harness?

THanks