How do I determine proportions for 3-stone ring?

[elrohwen]

I really like the oval spinel ring in this post! Creative use of side stones.

Engagement Ring Set - CVB Purple Spinel

I seriously need to share my excitement with someone and no-one I know really will appreciate my dorking out on the adventure of commissioning a ring(s). I only recently discovered Pricescope. I'm grateful I did! I adore my Mr told me to design what I want. And lucky me I get TWO engagement...

www.pricescope.com