In the recent Hedrick/Gagne video, Gagne made some comments about making the flow from the shower screen more even should make extraction more even. He didn't have data to back it up, but I agree it makes a lot of sense.

I've always thought the flow from my Alex Duetto was poor, so I got an IMS screen in the hopes of improving the flow. It did make some improvement but not good enough I didn't think. The E61 dispersion screw essentially has 6-7 holes from which water flows onto the screen, and then the flow from the screen seems quite uneven and random.

I thought about a matrix screen but then I've seen videos where the flow migrates to the middle and you just get a bit stream from the middle, and I thought an even dispersion right across the screen would wet the puck better, removing the surface tension of the puck and allow the water to penetrate more evenly through.

So then I thought, what you need is the water pressure building up evenly behind the screen before pushing through all holes in the screen evenly. So I thought maybe some paper filters under the shower screen might just do that, so the video below is the result. Pretty good I think! I'm not patient enough to do back to back taste tests, and don't have a refractometer to test extraction levels, but like Gagne I think it makes sense that this would make for more even wetting and therefore extraction of the puck.

To keep the paper as clean as possible, I use a puck screen for every shot and make sure I flush thoroughly, and change the papers once a week. I now have a 55mm and 53mm, 1mm thick, 50micron puck screen coming to see if that will be a more permanent solution.

Let me know what you think!

Whatever, i like the simplicity of your idea, if you can really feel a difference ( IMHO, greater extraction does not means always better result), you got the point.
A better/even water diffusion, is probably important until the puck is saturated, then some difference can occurs but at this point the water diffusion become less important, this is my opinion.
I myself modified few months ago an E61 group head water diffuser/sprinkler, to obtain radial streams of water inside the screen shower, i did got better espresso, sometime, and sometime not.
Anyway considering the simplicity of your idea, i'll give sure a try, but i suspect i could got the negative effect i had once i used a puck screen, a squeaky lever after only 2 months, but the curiosity is difficult to contain

This does appear (at least visually) to be an improvement. I'm not sure if I like oil soaked paper in my brew path but I'll be interested to hear how the puck screen goes.

Personally, when I tried the Matrix shower screen I got a squeaky lever in only a couple of days. I don't think these are a good choice for e61 groups. I wonder if a puck screen above the shower head would produce the same effect? I can't use a puck screen on top of the puck. I noticed zero difference in the cup and it was miserable to get out when hot.

Excellent find.. seems simple....must try...why not.