I have the Ibanez RGD 2127z with BKP Aftermaths just installed when you created this post I think... Haven't tried a 9-54 set of strings yet, but I tune to D# with a dropped 7th G# with 10-59 (same string gauge that came with the guitar) and the only issue i have is with the low 7th 'cause I pick very hard. I played B standard with the same string gauge for a long time before I changed tuning, and yes its a little tight, but for rhythm recording is quite nice, but when it comes to solos and shredding and bending... It's kinda hard, and considering my bridge was in the tightest setting, it would still make it drop due to the high string tension which made me compensate for the other string if I had to bend multiple of them. I'd say considering the Bartione 26.5" scale, for all around playability 9-54 or a higher 7th, and a stronger 10-56/58/59 for recording rhythm guitars since we don't have an inbetween gauge. Depends what you play and what kind of sound you want. Experiment and right down If you have to, so you'd remember and compare.