Sizing kit vs actual ring?

Hello all!

I recently ordered the RingConn Gen 2, but got the sizing kit sent before actually confirming my order. I am between ring sizes, which would be 7 and 8. I am planning to wear the ring on my left hand (non-dominant hand) on my index finger. I have tried using the sizing kit rings for both 7 and 8, but I am on the fence of what to get. The size 7 fits pretty snug and is a bit difficult to get off at times, but does not move around my finger during the day/night. The size 8 is easier to get on and off, but tends to move easily so that the sensors are not in place all day. My fingers do seem to swell a bit during my workouts and sleep, to the point the size 7 is impossible to get off and leaves indents on my finger. I have seen comments and posts online that the actual ring is a bit larger than the sizing kit rings, which is where my dilemma comes from. I know technically ring could be exchanged for a different size, but I would love to avoid that hassle. Any input would be greatly appreciated!! Thank you! :)