Convoy c8 -- few questions about oring/boot sizes

Ordered a XPLhi Convoy c8 from GearBest…

Have a few questions:

What size are the O-rings on the main body like the tail cap o-ring? are these 20mm?
What size is Lens o-ring? I believe this is 42mm x 1.5

What size is the tail switch rubber boot? I see a few options like 20mm boot w/ 16mm switch 8mm tall

Thanks in advance…

Tail boot is 16mm they should fit with 8mm

The orings can be 18 to 20mm as they can be stretched

42x1.5mm is the right one

How many o-rings are we looking at? Obviously in a month or so when light arrives, I could count myself.

Lens, (2) on body and 1 on tailcap? I was thinking it was only 3 total.

42, (2)18-20’s, 16?

Thanks for your help