Obdo non vtec ecus can rev quite high. My current daily driver has a stock b2 bottom end with a y8 head wide band tuned with a pm6 ecu that activates vtec through the a/c relay. I can rev my mini me to 8k without any issues. I'm not saying go rev your motor as high as possible. I am simply saying that it is possible to rev that high with a obdo non vtec ecu without suffering engine damage. My lc1 tells me that the a/f ratio stays pretty much the same from 7400 rpm to 8100 rpm. I wouldn't worry that much about it changing drastically on you. I have a ton of datalogs if you would like proof.
On a side note, I work closely with a ASM guy that is making a ng63 rom with additional rpm rows. NG63 will go to 9000 rpm.
If you can wait a month or so I will send you a copy when it is finished up. There are IAT and ECT multipliers available now within the ng62 roms. PM me if you want more info.