Here are the answers to your questions:
1) How fast the wt is lost can affect the amt of loose skin.
False. The skin has its inherent elasticity that is not affected by the rate of weight loss.
2) Loose skin mostly appears on the arms, thighs, abdomen.
True. The most common areas addressed surgically after massive weight loss are: abdomen, breasts, arms, thighs, neck
3) A lower body fat % and higher muscle compo. can aid the appearance of loose skin.
False or True, depending on how/when you are asking the question:
False because there is no direct influence of fat:muscle ratio to skin elasticity. In fact, as you loose fat, the subcutaneous layer loses its volume, and the appearance of loose skin will be more apparent.
True because at this point (after you have lost significant weight), if you choose build muscle mass, it may 'fill in' some the lost volume, but it all depends on how much loose skin and how much muscle you have.
4) The more wt you lose, the more lose skin you will have.
True, see above.
5) Surgery is the only option to get rid of the excess skin for good. I had lost 60 to 70lbs and is going for a TT. My arms are good but do have some skin on the thighs. Will it get worse with age compared with the average guy?
True. If you have excess skin, the only way to get rid of it is to remove it surgically, that is, non-invasive methods will not work. Yes, if you have had massive weight loss, your skin tends to be less elastic than someone who has not undergone the same degree of weight change, and it will get worse with age as compared to the average guy.
Hope this helps, Good luck.
Lawrence Tong MD FACS FRCSC