What size caps for evap?

[Postal Dude]

What size end caps do i want to fab a cap in cap evap? I have a piece of copper 1.75" diameter. Largest end cap i can source here is 28mm. On the internet i can get 35mm and 42mm. And even 54mm.

How many caps would give me the most efficiency? 42mm on the outside then a 35mm, 22mm, 15mm, 10mm.

Or would a 42mm - 22mm - 10mm be just aswell?

All guidance welcome

Sean

[tiborrr]

The more the merrier, keep at least 2mm wide channels.