The requirement for glycine for collagen synthesis is about 3-4 g per day. Glycine is involved in many metabolic processes when you look into amino acid biochemistry. Total human requirement has been estimated to about 10 g./ day. A small amount is synthesised. Unless a person is eating nose to tail or taking gelatin or collagen peptides (gelatin cut up a bit by enzymes) then they won't meet that daily requirement. The amount from eating nose to tail adds up to around 3-4 g per day.
Meat contains little connective tissue unless you are eating cheap cuts with a lot of tendon and associated material. Whereas various organ meats contain more collagen\connective tissue disperse through them. Hence, eating nose to tail involves consuming more collagen which has a different amino acid profile to muscle meat. Collagen is about 1/3 glycine. Collagen peptides contain a bit less as some is hydrolysed by those enzymes which make it a peptide (various from manufacturer to manufacture but more like 1/4 glycine).
Most modern humans are in chronic long term glycine insufficiency and so will benefit from eating nose to tail or taking a supplement. Methionine is also needed for health reasons. Glycine\methionine ratio is also important. Easiest way to achieve both is....
eating nose to tail or taking a supplement (gelatin or collagen peptide).
The above information may be verified by simply doing the calculations for amino acid intake etc using the relevant food groups. if you don't eat nose to tail, as you are topping up the connecitve tissue you are missing out on eating gelatin\collagen (including glycine). However, organ meats have other nutrients which you will not be ingesting if you do not eat organ meats.
Looking at the dose side of things it is pretty obvious that many modern humans are insufficient over their lifetimes and undoubtedly this contributes to chronic disease. Not only to do with insufficient collagen synthesis but also in relation to the many other biochemical processes that glycine is involved in eg neurotransmitter, sleep, heme synthesis (from memory) and various other ones.
EDIT: Missed the other side of the coin ie states of glycine\collagen excess. Some people might think if 3-4 g of collagen\gelatin a day is good for me then why not take more? It seems that one can feed large amounts to people and they may get so gut distress and thats about it. When done in short term feeding experiments. However, such large amounts of consumption don't occur in nature. So, the answer is that no one knows for sure if consuming excessive amounts of collagen\gelatin above the 3-4 g/day might lead to longer term consequences. It gets complicated as eating large amounts of collagen\gelatin might start to reduce protein consumption from other sources and interfere with amino acid balance or reduce consumption of micronutrients. Message 3-4 g/day of gelation\collagen seems like a sensible dose but more leads into an area of unknown effects which might have negative consequences.