I just put a set of John Pearse NuAge on my Martin 0-28, and so far I like what I'm hearing. I have been using the high end Martin SP strings and Thomastiks. I would definitely not use anything heavier than light gauge, something like 11-52 for the E strings - max. The Pearse NuAges I put on are 10-47 and are just a little light. If I like these, the next time I will try the NuAges that are just a bit heavier. The best thing to do is try several different sets and find the one you like. Good luck. -btmp