Well, I believe I have all the necessary tools then. Any last advice?

I hope it works!! I'd love to replace my existing dispersion screen with an E61 screen!

Well, good news and bad news. The good news is that it almost worked, well enough that I'm convinced that it will work given the proper materials and technique.

Zeb, which style and brand double basket do you use when you stretch a shower screen?
I'm afraid the one I used was too wide at the base, because it stretched the upper rim too wide for a gasket to fit in before it could stretch the muddle wide enough to fit all the way. I standard gasket wouldn't fit at all, but I was able to distort a cafelat silicone gasket enough to get a good enough seal to make coffee without any leaks.

With the proper shaped basket I think this method would work just fine. Now to order another cheapo shower screen to try again.

I don't know which basket I used, it was conical and more little. That's all I can say

I'm sorry, in vacations I forget a few things... I had to cut and sand the base of the screen. And sand a little too the inside of the group gasket. Sure it can be interesting to use Cafelat silicone gasket, more than rubber ones.

A Faema 14g basket perhaps? I used aN HQ 18g basket, probably too big. Why did you need to sand the inside of the shower screen?

I can see where you may have needed to sand the gasket to increase the inner diameter, I might just try that since gaskets are cheap.

I had to cut and sand the "lip" at the bottom of the shower screen *.

* Any English lesson accepted

Installation Success.

A bit of dremel-work today on the gasket and I got it all properly installed and working fine. I decided to detail the process with pics and a results video in its own thread: How to fit an E61 Shower Screen on a Zodiaco / Futurmat / Lambro / President Group in which I also thank Zeb for the initial contribution of this method.

Thanks Zeb!

Pleasure