I've owned many Heritages, since 1988, with the TKL cases. The H-150 and H-140 cases were perfect fits. I'm sure the H-137 has a similar tailored fit. I don't see any reason to transport them in anything else. My Peerless archtop arrived in a case which fit so poorly the president of the company sent me an apology and the company redesigned the case for the remaining of that model's inventory. I researched cost effective options to transport it and settled on a Mono OM/Classical gig bag which fit like a glove. The guitar has resided and traveled in that gig bag for the past 10 years without incident or intonation issues (floating bridge, floating pickup, and pickgaurd). That was a case where a gigbag was a good fit, no pun intended.