GIYF is a term folk use. Search for it.
Short back tends to be for shorter people and therefore long back for taller people. In the forces, the training staff tend to have that skill where they can advise you as to what will be best for you. But as you progress you can swap and change to find the best fit for you. If you were short and had a long back bergen and got down in the prone positon then you would not be able to raise your head. I think the short and long both have the same volume but just in a different shape.
Camouflage patterns change. The PLCE Personal Load Carrying Equipment originally came out in green/OG Olive Green, then there was DPM Disruptive Pattern Material and now we have MTP Multi Terrain Pattern. When you use them in an Arctic/Snow location you have a white elasticated cover, and for the desert you have an elasticated desert pattern cover. I think MTP has replaced Temperate, Desert and Jungle pattern uniforms. Many troops prefer the ALICE pack or the 80's style PARA/SAS bergen with the external GS General Service frame for use in the jungle as it allows air to circulate across the back area. All of the above relates to military matters but for civilian/Bushcraft use people often prefer good old plain green as it blends in well and is often seen as being less gung ho and agressive.
I have seen some wider shoulder pads that are slid up over the original straps and held in place with tape. Similar idea to the straps you get for car seatbelts. As for your question about which is best for you. I think you have to decide what your max load will be then decide on what you will need to carry it
Short back tends to be for shorter people and therefore long back for taller people. In the forces, the training staff tend to have that skill where they can advise you as to what will be best for you. But as you progress you can swap and change to find the best fit for you. If you were short and had a long back bergen and got down in the prone positon then you would not be able to raise your head. I think the short and long both have the same volume but just in a different shape.
Camouflage patterns change. The PLCE Personal Load Carrying Equipment originally came out in green/OG Olive Green, then there was DPM Disruptive Pattern Material and now we have MTP Multi Terrain Pattern. When you use them in an Arctic/Snow location you have a white elasticated cover, and for the desert you have an elasticated desert pattern cover. I think MTP has replaced Temperate, Desert and Jungle pattern uniforms. Many troops prefer the ALICE pack or the 80's style PARA/SAS bergen with the external GS General Service frame for use in the jungle as it allows air to circulate across the back area. All of the above relates to military matters but for civilian/Bushcraft use people often prefer good old plain green as it blends in well and is often seen as being less gung ho and agressive.
I have seen some wider shoulder pads that are slid up over the original straps and held in place with tape. Similar idea to the straps you get for car seatbelts. As for your question about which is best for you. I think you have to decide what your max load will be then decide on what you will need to carry it