Yeah, the sources are all anecdotal from here and collected by @KSman - he's like the giver.
Here's the deal. At six weeks you have six half lives from your first shot and your levels will be maxed at the dose you are taking. Getting blood done before your seventh shot tells you the lowest you will be on that dose moving forward. If your levels are over 1100 at that point, you should reduce your dosing. If they are 500, you should increase your dosing.
The problem is, if you take blood after seven days, that tells you your trough. So, what if your level is 850 at that point? You still don't know what your peak is, and it could be high enough to create excessive aromitization to estrogen, and then you may have a problem.
For what it's worth, I shoot 140mg once a week, IM. The preferred protocol on this forum is to shoot every 3.5 days subcutaneous. Shooting more often stabilizes, or evens out, T levels and minimizes the risk of converting T to E. It also minimizes the swings from peak to trough, so you don't feel great post shot and like shit pre shot. Same with SubQ. It is better.
But, I have no problem with getting funky after six days, and E7D works for me since I don't have conversion to E issues. During stressful times, I do shoot E4D, but it just depends on how I feel
And, the important thing to remember, is you may feel fine with elevated E levels, but it has negative effects on your lipid profile, so you do want to manage it better than just how you feel.
My father is 80 and he shoots 300mg E15D. His Internist is a close friend of our family, and he is smart enough to know he is relatively ignorant with respect to the cutting edge of TRT. I have been on other forums, and have found this to be, by far, the most knowledgeable. Personally, I don't take all of the recommendations here, but I know what they are, and whenever I have an indication that I might have a problem, I know what to do because I have read all of the stickies here and follow the forum closely.
So, that's why they test before your seventh pin, and it's a decent protocol. but, it doesn't tell you where you are post shot (you could be sky high), and it doesn't tell you what your midpoint is, which is also important.
If your doc or clinic doesn't test at these times, and you do want to know the numbers, you can get testing done privately at reasonable rates. I have used Life Extension, others have used PrivateMd labs, I think.
Anyway, just my take, certainly not an authority, may have fucked something up in this post, I'm sure some one will correct me. Bottom line, this forum is, by far, your most valuable resource moving forward.