OR - Fit a PCV and do a different map for each gear ? - **** I wish I had access to a Dyno.
Do the high lift cams make a monster difference to emmisions?
High lift cams will make a difference, but just with HC-emissions.
With a PC5 and gear selective Autotune you will just still need an unrestricted base map.
The stock O2-sensor has the right socket for the wideband sensor and you can make a good map without a dyno.
But it is far easier and probably less expensive to manipulate the gear sensor and make just one map on the dyno using Tune-ECU. It should not take much more than an hour.