If you use a decent fine line tape or even some insulation tape you do not need to do this as paint will not creep under fine line tape,,,,,,,,,,,, go to Ebay and simple type in 3M Fine line tape...I use this in work all the time and have never had creep under it....I spray buses Lorries with multiple paint colours so I think I might know a thing about masking.
A TOP TIP here....when you have down say for example the red antifouling and have obviously masked it up for the satin black hull spray the sating black on,when you are happy with it WAIT 30 mins and demask it straight away....yes I am CORRECT in what I am saying here....make sure your hands are clean then simply RUN your finger along the paint joint using LIGHT PRESSURE this WILL make the join line flat...if you leave it more then an hour then your are stuck with a hard edge.
Trust me on this it WORKS...dont Believe me then ASK Tug Kenny
Dave