Basically the issue comes down to performance. The chain will rattle at times if the adjuster is at its limit.
If you are at 1.1 don't worry about it. That is only 0.004in over the limit and like I said before it will work OK. I have done it.
Was the head planed on both sides. This is important as the top surface will still be warped if it hasn't been planed. There won't be room for another cut! The cam will bind if the head isn't flat on top.
Bosch Master, ASE Master, L1
33 years MB technician