May want to heat the letters with a hair dryer. When stripping letters off of my work vans, it was always much easier on a hot summer day. Make sure you wear rubber gloves. I've never worked with acetone, but the oven cleaner burns a bit.
'97 Prostar 190 - LT-1
Prior boats - 2009 X14, 2008 X14, 2005 197, 1988 Tristar 190, 1989 Prostar.