Talk to anyone who is an Athlete who is hyperthyroid and you will not find someone say it improved their performance.
First off to get benefits of weight loss you have to have elevated thyroid hormone and thus develop exercise intolerance and mitochondrial dysfunction leading to worse training.
Also the body attempts to protect itself from hyperthyroid state by down regulation of deiodinase type 2 to block active forms of thyroid hormone in the body at the tissue level. Hence the system tries to keep you at certain levels and so you need to overwhelm the system to derive "benefits."
So this weight loss of 3-4 lbs will come at the expense of fatigue, exercise intolerance, possibly muscle loss as thyroid hormone is catabolic and then you gain this weight back when you have to come off it and let your own thyroid axis.
Not a great ped in my opinion where you increase muscle mass, rbcs, or ability to recover with testosterone ,epo, hgh.
So you can talk about numbers all you want either this ideal tsh, but until someone comes in with an RTC showing use of thyroid hormone enhances performance especially in distance running, you have not proven your point!