Read my post again, completely different burrs. 64/83mm HU is bimodal traditional espresso burrs and 80/98mm HU is high clarity unimodal burrs

This is wrong. 80mm HU is Weber Ultra. 80mm HU is the most unimodal burr available whereas 83mm HU is a bimodal burr

I've seen that video but have found my water to make a huge difference in taste. I've tested a lot of different water filters and there's a clear taste difference for me. Going from BWT filters to ZeroWater and adding tap water was my biggest coffee upgrade in a long time. I currently use ZeroWater ...

Look here {link} full height with lever raised is 60cm

With a Speedster skip every 64/83mm grinder as it'll be subpar for the Speedster. Buy a better grinder like most have mentioned here to get the most out of this beautifull espresso machine

You're group gasket is probably getting hard. Try putting a new one as that's the problem in 90% of the cases. Maybe the lip of the single basket is just a tad lower and thus not tightning far enough. I did always love the Cafelat silicone group gaskets

It's indeed not bad to drink distilled water with a good diet but it's bad to make coffee with distilled water as it tastes worthless. A proper extraction needs minerals to make good coffee and that doesn't work with distilled water. Better to descale a bit more often and do maintenance regularly th...

I see you already own an EG-1. The Ultra burrs are just as good as the 98mm brew burrs. Here's a comparison between the 64mm MP and the Ultra "SSP MP versus SSP Brew versus 80mm Ultra"

Keep in mind that the max pressure can only be reached if the coffee gives enough resistance. Yours is set to say 12 bar and will give X ml/s of water from the pump. If that maximum amount of water gets no resistance there will also be no pressure (so without coffee) on one end and you get the 12

The Kafatek will crush the Zerno. Those 75mm burrs will outperform the 64mm in the Zerno in every way