Sounds like we've got close cousins- I have a 1970 HD-28 and a 1972 HD-35. I use the Dampit series with the clear plastic soundhole cover- the green tube is hydroscopic- about every third day I re-dunk them- then back into the Martins- they also feature a Humidity metering visual strip- about 50 to 60 when they are in their Geib cases is best for where I am in Central MI--If you need the info- it is Dampits, Inc. PO Box 493-- Radio City Station New York, NY 10101--
I bought the grandkids (5 and 4) the Baby Taylor for Xmas-looks like they'll have fun- I started playing about 15 years ago- mainly Blues and Bluegrass. I also play Dobro (std G open tuning) and a friend is teaching me the upright Bass too- never too old to learn--