Do you really need to know when you're AT redline?

I know a guy with an '85 CRX Si with a B16 w/CTR cams, stock tach. It's really not a big deal, by the time you hit VTEC and the needle is racing toward the end of the tach range, you should be shifting and grabbing the next gear.

If it were me, I'd probably just get an adjustible shiftlight and set it up for whatever RPM I wanted past what is readable on the tach.