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
