Hello,
I just read all comments under this thread now. Hope this helps your selection.
I have 16.5cm wrist circumference and am 172cm tall.
3861 hesalite: 47.5 LtL, 13.54 thick
3861 sapphire: 47.5 LtL, 13.18 thick
New fois: 48 LtL, 13.38 thick
321 EW: 48 LtL, 13.7 thick
I have 3861 hesalite, 3861 sapphire sedna gold two tone and 321 EW. I have not even tried new FOIS on wrist.
My wearing experience & how I feel:
- 3861s: both sit very well on wrist. I don't feel the difference in thickness, probably because their steel case dimensions are exaclty the same but only the glass shape different- flat or domed, hence the 0.36mm gap. I feel them exactly same, when speaking of size 'only' (including thickness) on my wrist.
- 3861 vs 321: Now, it's tricky part for me. 321 feels more like a hocky puck. I feel like I am wearing 'something' in a not very good sense compared to 3861. I am not saying it does not wear well - it's only relative to 3861, and it's an evidence how genius the design logic is for 3861 despite its seemingly not pleasant size and dimensions. I think it comes from a combination of a few things - longer LtL, thickness and bracelet. Comparing the two different steel bracelet, I think 321 is better in terms of aesthetics and how it hugs the wrist, but that very chracteristics make it support less well the watch's case when it's longer and taller than 3861 case, and makes the case & head of 321 EW move more on the wrist. LtL, thickness & the softness of bracelet - each one when taken into consideration individually, does not make a big difference, but all combined, it makes a difference to me. I read comments here by other users saying no difference, so I again believe how it wears and feels are all very relative.
So what I did to 321 EW? I bought an original Omega black alligator strap a few months ago, but only felt it made the wearing experience worse, because the leather won't sit tight on my wrist so it makes 321 EW even taller on my wrist. Also, from aesthetics, it's strange to say, but it is less beautiful than seen on others or from pictures. So I recently came back to the original steel bracelet.
Lastly, here you go with pictures of my 3 speedmasters. The one with a black cushion is 321 EW.