What's the heaviest gauge string anyone's fit on the Yamaha TRBX505? I'm getting one this week and I want to drop tune to AEADG and ADADG. The Kalium string tension calculator shows that the low A should be a .148 to have comparable tension to a .130 at B. I'm wondering if the .148 will fit in the nut without having to file it, though, as I don't want to immediately void the warranty.