Underlay & Top Print / Mesh Counts?

Interested to hear how you guys print exact PMS colors on dark garments w/ an underlay, in regards to how you get it done. I'm very new to the game and started out thinking you had to choke every underlay, but then an old vet told me it's easier just to do the underlay w/ a higher mesh count and the other print with a lower count.....right now I do alot of white on black, w/ using 195 for the underlay and finish it w/ 156. Just wanted to hear you guys insight and thank you in advance!