i mixed fronts and rears all the time, had a heavy EXUP 1000 and had no problems at all ever, as long as you do have a stickier front than back . but this is only my personal opinion. i used to use 020's as well and they are a cracking tyre, well sticky enough for our c**p roads, so good choice you made there.
the 014's on my GSXR were pants i thought, they just wear out fast, but again this is only my personal opinion.....