Itâ€™s why Iâ€™m not buying more expensive latex tubes when the butyl ones work just fine. Theyâ€™re not making my ride anymore enjoyable, and theyâ€™re not earning me a PR, and theyâ€™re not earning me a podium. So in my estimation why bother?
When I put on race tires as oppose to heavy training tires by the time Iâ€™ve ridden around the corner I can feel and see Iâ€™m faster. Same with my A2. I can confirm it through strava segments and a faster overall velocity. If I rode that same ride 10 times the 5 on each the stats would be lopsided.
I'm curious as to your testing protocol where you can determine latex to have little to no effect, but you can tell the difference with tires and your helmet.
I personally have a 4.5 mile hill that I train on all the time. Probably did the full climb over 500 times with a power meter, and have done hundreds more power intervals in the middle over the climb. It's relatively sheltered from the wind, and a steady 6% so it mitigates things like your position, or how aero your kit is so you can test things like rolling resistance and weight differences.
I've got this hill so dialed in, that I can pretty much predict my time knowing what kind of tires/tubes I have on, how much I weigh (person, bike, gear), and how many watts I put out average. I can say that over many tests, that latex is indeed about 4-5 watts faster for me. I've also confirmed that Gatorskins roll about 15 watts slower than GP4000S tires on this climb.
Maybe I have a magic pair of latex tubes...or you inadvertently bought a fake pair. Or maybe...just maybe...you need a much better way of quantifying what latex is or isn't doing for you.