The General meter would probably suffice for baseline/then future tracking and monitoring but would require much work and comparison with another mete,r with known values, to get some accuracy out of it for spot readings without a base line..
On any boat you can almost always find some known dry core. That could become a baseline but then the question becomes what is elevated, moist, wet, saturated? Is it 25, 30, 44, 68? Unless you had a meter to compare it to that defines those ranges, it would be very hard to guess at how wet the deck was without core samples..
A small brass or phenolic (plastic) sounding hammer can tell you a lot if you train your ear well and they really do cost peanuts.
I have used lots of different meters over the years (Tramex, Soverign, JR Overseas etc.) and the CT-33 is the best bang for the buck I've come across. It replaced my old JR Overseas GRP-33 that I accidentally dropped off a boat and the CT-33 works just as well, for about half the price.
I agree with the comments on General Tools. They are Generally mediocre to Harbor Freight Quality with the occasional decent tool thrwin in the mix. That meter may be decent on glass but would not be high on my priority list, due to the unknowns. If I really wanted to map and monitor my boat or use it when looking at new used boats I would wait a while and save up for a meter desigened to read glass laminates.
One other thing to consider is digital vs. analog. I much prefer analog in a MM. The digital ones are very hard to track as the numbers on screen are an ever moving target vs. a needle. You'd probably need to use both side-by-side to see what I mean..