You might want to check with enginbldr to see if he expects that cam to increase idle HC. Sometimes higher lift cams will do that. You've done most of what I'd suggest. I've never tried the magnets - who knows. . .

One other suggestion is to get the engine hot before going in for the test. A cold engine makes more HC. You want it fully warmed up - not just the coolant, you want the whole engine warm - a 20 minute drive at moderate RPM. If there is a line at the testing station, don't just let it idle, rev it up occasionally to keep things warm.