I just finished my Taxi paint and decals and struggled with HVLP and colors along the way so maybe my story will help:
I backed into HVLP due to Vid's cabinet guide thread recommending Kilz oil based primer but I couldn't roll that well so went to HVLP and thinned the primer with naphtha (per Vid) 4 : 1 to get it to flow which worked out well.
For color, started with the Behr 3300 color recomendation in this thread and elsewhere. Took the color code to Home Depot but they couldn't decipher it. Went back with a piece of the new decals to scan and mix. Got home and knew I'd have trouble with spraying because the 3300 was so thick. Thinned out with water to 20% which is twice the recommended amount, still too thick, tried to spray with bad results and it was tacky after days. The excess water was probably affecting the chemical reaction.
Then went to Sherwin Williams for oil based cabinet paint and HVLP recommendation. They had no one with HVLP experience but scanned the decal and mixed the paint which is only available in gloss. Sprayed the cab (again 4 : 1 naphtha), went on good but the color was not right. Apparently the scanner was picking up mostly yellow and not the red which is very fine specs on the decals. Back to the store, scan and mix, color didn't look right in the store so the rep custom mixed another adding more red. It turned out to be a close match and complimentary to decals.
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