Ok another wonderment. End grain, we all know it can be difficult. If end grain, and glue is part of the equation, are you feeling some openness in the end grain to allow the glue to flow in, makes for a better join? Or are you thinking that if you shoot, sand, or burnish that end grain so it looks more like edge grain, that this works better?
I have started making 2 of everything, and am doing one each way. I don't have any machines that check strength, or meters to measure, but you can get a sense of whats working better.
Over 50 years ago I grew up thinking you just accepted it was weaker, and didn't really do anything to try to change that. Now we see videos where a guy suggests it to be a strong joint. WHOKNEW?