So I'm not an expert but from my experience there are two wrong assumptions that you are making.
First one: the belief that carrier oil influence the metabolization of a substance so much to make a big difference. It doesn't. A substance in full castor oil may have a delayed absorption of maybe few hours.
A mix of castor and MCT will have a even less meaningful impact.
The reason for mixing carrier oils is not to extend half-life or delay onset is for the properties of some carrier oils have, like decreasing inflammation, a slightly painkiller effect, antimicrobial etc. Changing the viscosity of the oil as well.
I have found that thinning the oil too much make it yes easier to inject with slinpin but it's very easy for leaking subq and those become nasty very quick.
Second wrong assumption: thinking that the more stable the levels of an hormone the better you will feel. This is a paradox but if you do limit the side with stable levels you at the same time limit all those "positive sides" like raging libido.
If you have cycled for a while you will notice that usually you have an increased libido at the Start of a cycle and then it plateau around mid cycle and continue to slowly decrease or stay stay the same the longer you go.
This is because the body adapts to the level of hormones and it becomes the new baseline for that time.
Prop gives you stronger libido erection etc exactly because you have continuous peak and valleys. If you try to extend the half-life making it more stable you will defeat exactly that precise effect it gives you.
Of course with more pronounced peak and valley there can be more sides but Because chemically speaking sides are not just the "bad" one, sides is to whole plethora of effects a substance gives you some are considers positive and some negative.
These are my 2cents and not the universal truth
You are wrong on both explanations but by wrong I mean real world data versus lab analytical data, experience versus chatgpt...
For one I know a person who has several bodybuilding clients and she prefers to get her gear from someone who makes it with extra thick carrier oil, not sure but guessing full castor. I've offered many times in the past to get her what I consider to be superior product and she has tried and found her clientele all prefer steroids in thick oils. And they've tried both. The reason given is that the thicker oils last longer and release more slowly than thin carrier oils. They pack more punch, it has nothing to do with oil viscosity and ease of injecting.
According to you the difference is a few hours, and perhaps on paper that's true. We bodybuilders arrive at our conclusions based on what we experience as we experiment over time. Guys In lab coats do not understand this.
Your second statement, that stable blood levels of hormone is not ideal, is wild. The body has negative feedback loops you must realize this and the faster you 'rock the boat' so to speak the more severe the bodies attempts to 'right the ship' in response as it attempts to restore equilibrium are.
If in the real world things worked like you assume they do, we would all be pinning our steroids as esterless suspensions, but anyone who has actually done that will tell you straight up 'side effects in a bottle' is an accurate statement.
Esters are added to steroids firstly for convenience (so daily injections aren't needed) but secondarily (and equally importantly) the longer esters lead to more stable blood levels which in turn are more useful for our purposes (muscle building) as well as reduced side effects as the body is able to actually adjust to the new state and doesn't go crazy releasing myostatin or shutting down endogenous testosterone production trying to get things under control. That is precisely what happens when hormone levels dramatically spike.
You are somewhat correct in thinking that hormone spikes can have some usefulness for bodybuilding (and it's true that they do) but for the sake of context here, unless someone specifically is looking for a two week blast and then lengthy PCT (Paul borreson advocated this) then skyrocketing hormone levels is a terrible idea.
Why?
Because in these circumstances the body stops responding to hormones altogether, fast. Two weeks fast.
Think about oral steroids, perfect example: Dianabol Superdrol and Anadrol, what do they have in common? Most people report magic for the first two weeks or so, and then you have to nearly double the dosage to get anything and past 4 weeks or so taking more basically does nothing. The magic is gone.
The only way to get it back is coming off or switching to a different oral.
Why?
Because orals kick and are completely gone In a matter of hours. The body hates that. It's defense mechanisms kick In full force and within about two weeks the steroid (at that dosage) is ineffective.
I don't mean to sound like a dick but when you are coming across like you are an educational resource to others one would hope you would actually be correct. It's questionable that you are even getting into discussions like this, you are not anyone's friend much like our parents were not our friends. They had a job to do, preparing us to survive. Didn't matter if we liked them or not, and the same applies here.