Souplex razor thread size identification ?

Let us know how it goes. After using the Souplex a few times I like it very much, but the handle is a bit on the small, light and slippery side.
 
If the thread is right, I'd like to have a handle made like this:



Diameter app. 12.5 mm, length 100 mm - here with an (aluminum) iKon/ShaveCraft 103 "Open Comb" head.
What do you suggest - one in aluminum (weights 29 grams) or one in stainless (weights 90 grams) ?
The original Souplex handle weights app. 15 grams.

I think I'll decide for aluminum, but not 100% sure yet ...
 
I would say either is an improvement! The Souplex itself is nickel plated brass (I think). The knurling looks like it will give a good grip.