since you are taking exo GH, your natty GH will be 'suppressed' not sure by how much, but people say lr3 usage can suppress your natty GH, well you on exo gh so i say go combine all two as long as you can,
but remember lr3 is shitty compared to GH induced igf in your MUSCLES,,,lr3 just floats around systemically doing insulin like actions and not much more
your call