RE: Too much protein = increased MYOSTATIN = bad
skinny - I'm not sure there is a definitive "it must be this" type answer. Most publications reference 'per lb' of bodyweight, but some other 'per kg'....so that for starters should convince you that its not an as exact science as we would like it to be.
For me, it comes down to what gains are you personally seeing? I have been on about 250-275g protein a day for the past few months and currently weigh 308lbs - so with one measure its too much (the kg measure) and with another its just about enough (lbs measure).
However I have made good gains over the past few months (strength and mass), so I will keep to this number whilst that is still happening. I think you need to forget numbers, and monitor how it is effecting your ability to lift & grow, and then adjust accordingly!
Nothing is worth more than this day...