You do not need any thing bigger than 65mm if you're running stock motor. I think it'd be crucial to upgrade to matching intake manifold and higher lift cams, for a throttle as big as 70mm.
Even 65mm is too much with IAB plate removed. You're already at the point of losing low end, with an even bigger bore, you'd further lose ram velocity. Bigger isn't always better.
65mm is the biggest Honda made for these engines, and it only came with H23, F20C, F20B MT and H22 TypeS, all of those engine have higher lift cams.
Anyway, here's one:
https://www.pakwheels.com/forums/car-parts/231381-f-s-h23-65mm-honda-throttle-body