I'm still testing the Matrix shower screen, but now we seem to have, in just screens using IMS 200 technology:
"BIT" E-61 - most of the center of the screen blocked;
"Precision" E-61- center of screen blocked like normal; and
"E&B Labs" E-61 - much less of the center blocked.

You can see these screens at TerryZ's store: https://caffewerks.com/collections/shower-screens

Also, note the "BIT's" new "BoB" and "Renato" basket designs ... https://caffewerks.com/collections/baskets

The cynics among us may assume these are just another way to lighten one's wallet, but I'm curious - although not curious enough to order.

(No affiliation with CaffeWerks or IMS other than being a customer.)

The E61 does not have a built in dispersion block above the shower screen, like many other groups, just a casual screw on the water inlet. So there may be improvements to be had on the water distribution with a good shower screen.

That being said, I have a hard time figuring out how this can be important if there is enough headspace between the showers screen and the top of the puck. In other words, if you have trouble with uneven dispersion, use a deeper basket.

It's more that the BIT is in terms of hole placement the exact opposite of the E&B - at first glance, one of these approaches has to be "wrong" if shower screen hole placement matters in an E-61 group.

Different groups have different dispersion block/jet breaker designs so I could see how different shower screens could have different impacts. For example, many think that commercial lever groups want holes everywhere.

As an extreme example, slowly lifting the lever in a la Pavoni results in a jet of water (like holding your thumb over a garden hose, only the thumb is the lower piston seal). That jet would go right through an IMS 200 shower screen if the shower screen was unfortunately placed so one of the screen's holes lined up with that jet of water. This lead to the invention of the "puck screen" to keep the jet of water from burrowing into the puck. Now people are using puck screens on other machines - but is the benefit on extraction of the puck screen in those machines: the screen itself, or the additional head space those screens require, or do those machines just have poor dispersion block/puck screen combinations?

So it sounds like one might expect for the BoB basket ... a change that seems consistent with what happens when going from a 'precision' slab-sided holes-everywhere VST-ish basket to the more traditional EPHQ holes-not-everywhere style; combined with the difference between those baskets to IMS' "The Single" basket of a few years ago. (The 10g "BoB" looks alot like "The Single.")

In other words, nothing has changed in seven years. Skip to 2:45 for Chris Coffee's Sept 2014 evaluation of the taste differences of "The Single:" P.S. I wonder when nutation will make a comeback .