Just a word of warning about sticking you head under your naked portafilter watching the flow. It can be dangerous, as I found out this eveing!
Somehow as the pressure rose the portafilter managed to turn and fall out showering me with hot grounds, water and a portafilter Lots of sore bits, but no proper burns, but I think I was lucky.
Not sure quite how it happened, but my naked PF does not lock in that far (as it has tedhnically the wrong "ears" for my group) so I guess this was to blame. Never done it before in 6 years though. I think my over pressure valve sticks sometimes (new one already on teh way) and so the pressure ramped up tofull pump pressure. Whatever a 9 years old vibe pump can deliver. The new 8mm gasket seems thicker then previous ones which adds to the locking problem.
I'm beginning to wonder if teh olf Rituale doesn't like me any more and perhaps I should be thining about a new machine