if you mean the russian 1.0, i also prefer it a bit more because of the air flow screw as opposed to the ring in the 2.0.V1 IMO and from what I have read.
Here are 2 bases at FT that are basically the Russian 91% V1:
$6.31 Kayfun Mini Styled RTA Rebuildable Tank Atomizer (2.5ml) - stainless steel + acrylic / 22mm diameter at FastTech - Worldwide Free Shipping
$3.51 Replacement Base for Kayfun Lite Plus - stainless steel / black plated at FastTech - Worldwide Free Shipping
The fill hole may not be as recessed as a R91%.
but the 2.0 has some improvements:a better insulator for the deck,316 SS vs 304 and a regular drip tip with no need for an adapter.