I see that you have come up with a plan already. I had this post recommending injections already composed, so am posting it anyway FWIW. I also address issues that apply to testosterone supplimentation in general.
I use injections. It is the only thing I have ever used, but can't understand why anyone would use anything else. It's the most effective, most convenient, and least inexpensive.
With creams or gels, you never know how much is being absorbed. You read here about guys having to increase their dosages, try different brands, etc. With injections, you know exactly how much is being absorbed -- all of it. In reading most of the posts on this topic over the last couple of years, I don't recall anyone switching from injections to something else.
The cost is about $5 per week, including syringes and needles. The pain ranges from non-existant to minor. It takes a bit of nerve to jab myself but I can do it. It is easier just to let DW do it. In the two years I have beem taking it there have been two or three times when the needle hit a nerve and it was painful. Not bad, but worse than the typical briar-stick feeling.
The usual criticism of shots is fluxuation of testosterone levels between shots. I do it weekly, and noticed some fluxuation at first. The low times weren't bad -- just the erections weren't as reliable, but usually enough to get the job done. We would move the injections around a day or two if we had a screw date planned to compensate. After about 6-9 months I noticed no fluxuaion. One could always take it twice-weekly. Then there is no way you would notice any fluxuation.
Also, I think shots take the longest to take effect. A month to notice a definite improvment, and two to realize the bulk of the benefit.
Pellets would actually win the convenience prize. However, they are expensive, painful, and cannot be removed. They do not show up on X-rays. If you get too much, you are screwed -- you have to wait until the pellets disolve. Also, they are not sterile, so there is a risk of infection.
As for your testicles shutting down, thatmay be prevented with conservative dosages. Mine have not shrunk, and their output has actually increased. I was around 700, but was 800 on my last test. I cut the dose by 20% and am still fine. You want your nuts producing as much as they will. It is more natural and normal-feeling. If we are concentrating on sex and our marriage and I'm feeling the love, I can go 4 times in 24 hours. If the situation doesn't call for it, I can go two or three days without it.
And be sure to take zinc & copper. The Zinc slows conversion of testosterone to estrogen. The zinc depletes copper, so take that too. I also take DIM.
All the best!
Everything you ever wanted in life is just outside your comfort zone (Jamie Lee Curtis)