The first thing you will notice if the adex dose is too high, is a blunted libido. You can titrate the dose based on that alone. If your libido becomes sluggish decrease the dose, if it is fine, but your retaining too much water, or you nipples are sore, increase the dose.
Your starting dose should be .5mg every day and then increase or decrease as you need. That is what's great about the liquid version - the ability to titrate the dose as needed.
As for injectable adex - it is possible and I know some UG labs will put it in their prop or sustenon products. I personally prefer everything separate, as it makes it easier to adjust things to suit you specific needs.
Don't missunderstand me however, and inject the oral solution. Adex will work injectably, but if it the product says for oral use, then use it orally.
I remember some poor fool injecting femara once - it had been suspended in 70 proof alcohol - the poor fool lol!