How quick in your experience will the symptoms appear if the base ring is too small? Meaning testicle color change and/or temperature changes...
I find it depends on how tight you are at the time. If you are loose everything could look fine for a while- If you tighten up things could change quickly.
I found 45mm was a snug fit during the day and felt 'right' but due to nocturnal erection attempts would cut circulation off to my balls and wake me up. Moved up to a 48mm and seems to have alleviated that.
Well you have to test the right size. I started with 4,5 cm diameter. Then i used because of a better fit a 4 cm Ring during the day and was a little bit afraid to loose my balls and getting impotent in the night with it. So i ised a 4,5 mm in the night. After my Lady reassured me, that impotence or ied off balls werent a problem for her i tried the 4 cm also during night. And it hasnt been a problem. If I get aroused or get a morning cock i woke up because of the pain sometimes. Now I seldomly het a hard cock anymore and the turgor of my cock shrinked. Like the life sent out of it. So i will switch to a 3,8 cm soon. I think. The effects if a tooo tight ring will occur fast or you wake up because of it. You have to try different sizes. It is not only the ARing it is also the width between ring an the tube which leads to an effect.
A simple guide is you should be able to get a single finger underneath it. If your balls feel cold or become discoloured (penis to) then it’s to tight, depending on how tight it is it could take only a few minutes or a hour or so.