Well, I would not sweat calculating your T/E ratio. Here's some basic info about it though:http://www.peaktestosterone.com/Testosterone_Estrogen_Ratio
The bottom line, though, for middle-aged and above males is that we just need to get our estradiol in a good range - not too high and not too low - and maximize our T. Imo men do best with testosterone between 500-700 based on emails that I receive. However, there is considerable variability with that and, as I've mentioned, some men are just great in the low 400's without apparent symptoms or health consequences.
So here's the bottom line imo:
1) You want to get your T to the point where you are symptom free. You must look at things like weight gain and mental fog as well.
2) Again, you want your estradiol in a reasonable range - not too high or low.
3) You want your free T between 1.5-2.5%, ideally 2%. If your testosterone is lowish and your free T is 1.5%, that could be an issue.
4) Make sure your thyroid is okay.
Imo if you follow the above three rules, you don't need to directly worry about SHBG. Now it's true that SHBG is a factor in the above, but it's quite variable and the above three have been studied more. In addition, if you correct the above three, all the rest will generally take care of itself.
If you can get yourself in these ranges, along with a good diet, exercise and maybe a few of the important supplements, you are going to dramatically improve your quality of life.
You don't want to be just surviving - you want to be thriving...