I don't think it will make any difference, but I might suggest for EX4300 running 14.1X53-D45, and 12.3R12 (or 12.3R12-S6) on your EX3300, versus 15.1[period], even R6-S3.
I know this functionality works with Aruba, but no real experience with 15.1 in such environments.
Just FYI and good luck.