Mature Metal discussion

I have the sizing rings ready, but I’m most unsure about getting the inside diameter measurement correct.

I’m a grower—just over 8 inches when erect and quite thick, with a circumference of around 6 inches. I want to nail this down because I’m worried that if I get it wrong, going hard will be really painful.

So my main question is: how do you properly slide the measuring ring onto your shaft? The only way I can manage it is by pulling my penis away from my body, slipping the ring on, and then getting slightly erect again. It’s hard to tell if that makes it feel too tight while doing so. Also, am I accidentally stretching myself thinner when I pull out like this, which might lead me to buy a size that’s actually too small? The issue is that when soft, my skin has some wrinkles (likely because of the large difference between flaccid and erect sizes), so it doesn’t just slide on effortlessly. What happens if you end up with an inside diameter that’s either slightly too narrow or too wide?

Here are the measurements I’m currently considering: Length: somewhere between 2” to 2(1/4)” … usually measure closer to 3 inches, but knowing my past devices, I know it can seem smaller. Actually thinking about going even tighter at 1(7/8).

Gap: sticking with the standard 3/8”

A ring: either 1(3/4)” or 1(7/8)” … might just buy both, as that part has caused me pain before.

Inside diameter: 1(1/8)” or 1(1/4)”… mainly worried this specific measurement could be too constricting. Not sure how to measure it accurately though.

Sorry if I’m asking something obvious; I just want to ensure my measuring technique is spot on since the inside diameter isn’t adjustable. Let me know if you need clarification on how I’ve been trying to gauge the shaft.