What shank width for stacking rings?

[blingbunny10]

About to go through with first custom work with DanielM, and have decided on stacking gemstone rings with silver shank and rose gold bezel, like these:
http://www.etsy.com/transaction/71485753????

How wide do you think each band should be? I have short fingers, and this will be for my middle finger (size 5.5). 2.0 is probably too thick.... 1.8 as pictured, or thinner? I have zero experience with stacking rings!

 

[pandabee]

1.8 would be fine. How many are you planning on stacking?

 

[papigal]

i would go for 2mm.