I ordered my RSVP 49mm tamper the same time I ordered the ROK. All but a couple of reviews that mentioned the ROK said it fit well. It doesn't fit very well. I'd say it functions about the same as the scoop. The edges are really really rounded. When I selected tamper this time, I just picked another cheap Chinese one, but I chose 51mm instead, and looked around until I found photos that show that the edges aren't so round. Check eBay, they sell for about 15 dollars US. I'll report back on the quality when I get mine, although the one I ordered is not available at the moment.

I saw an old post where aecletec (Chris) mentioned that he sometimes uses a 49, sometimes 51. It seems the 51 is the best fit, but because of the tolerance it can't go below the ridge. I'm thinking an 18 gram dose will pack plenty tight before it hits the ridge.

Concerning tamping in general, I have been having a tough time dialing my espresso in for a long time. A couple days ago I read Matt Perger's blog about tamping, and decided to give it a try. Find it here: http://www.baristahustle.com/how-hard-should-you-tamp/. It was kind of a breakthrough for me. I've always liked the idea of using a light tamp, but when I started doing this, I had my grind dialed in from totally choking my La Peppina to just right by my third shot, and never had a bit of trouble since.

Okay, I got my 51mm Chinese tamper. I'm really impressed with the fit and finish on it! It is a really, really tight fit in the stock basket though. I had to do quite a bit of sanding in the basket to make it fit . And if I don't put it in perfectly level, it binds. It's good practice for tamping straight. I haven't taken my calipers too it, so I don't know what the exact diameter is.

I also got my Mahlgut coffee grinder at the same time. When I pulled a couple of shots, I got tiger stripes like I've never seen before, but still the same phenomenon with the filter holes. This time, it looked like I was using one of those "double spout" naked filter baskets they talked about on "the craziest thing I've seen all day." I can't see any irregularity in the size of the holes, but I'm still wondering if the basket is to blame here. It's just way too consistent. It looks close to the same whatever I do in prep. I've even experimented with using custom dispersion screens (I took the screen and silicone gasket from a steamtoy espresso machine and laid it on top of my basket, then tightened it in), and it looks the same. Maybe my mistake was chopping the portafilter. I must say, ugly pour notwithstanding, I did get a pretty tasty cup. I just have the feeling that I could be getting better extractions. I may decide to get a new basket, but I should probably play around with what I have more first. I don't make espresso very often.

I wonder how well a Europiccola single basket would work with the ROK. I like using smaller doses, but I've read that the ROK doesn't like a lot of headspace. I still haven't dialed my variables in enough to confirm this, but I'll keep working on it.

I couldn't get anything I really liked drinking from the single but the double is great!

I guess I'll shop around for one then

I found a pair, single and double, from Brooks Espresso on Ebay. http://www.ebay.com/itm/La-Pavoni-Europ ... SwNphWYWzL Only, it didn't say if it was for Millenium or pre-millenium Europiccola. I already wrote to ask them about that. If it's the right size, I'm leaning toward getting those. It's cheap enough, and they look like they're pretty well made.

You said you got an original and a generic, how do they compare? And are they at least a teeny bit wider than the ROK basket? I'd be happy not to have to sand down another basket

By the way, what did your experience with the original basket? I'll have to keep fiddling with my dose and distribution. Maybe I'll find it is me and not the basket after all causing the cosmetically inferior bottomless pours.

The generic perhaps-Breville basket is about exactly the same size, while the La Pavoni is wider.