The question is not entirely clear to me (I'm not native english): ZP mark (or 0 on the scale, if aligned with ZP) is for orientation only, to do not touch the burrs accidentally, so if ZP is not equal to 0 on the scale (0-scale is not aligned with ZP, not calibrated), it's good to know, where on the scale the ZP is. If the scale and arrow pointer are both fixed (sticked to the grinder or engraved), there is no way to re-calibrate the grinder w/o removing/replacing the scale or the arrow pointer for new (changed) burrs.

Peter_SVK wrote:It might depend on the roast level, dose, basket size (diameter, number of holes), I don't know. I use 20g, IMS H32 (32mm height) basket for DC (nominal 54mm diameter), omni-roast (light).

I used 18g on my Lelit Bianca with VST 18g filter basket. The first pull I used 18 grids from zero. It took 58 seconds to extract 36g espresso. The second pull I used 22 grids from zero and it took 32 seconds. Using 20g beans in a 54mm basket is about 23g in a 58mm basket, but I don't think I could use 50 grids even I added 5g at that time because the 4 grids leaded to 26 seconds change . Maybe the water debit is also a critical factor. The Bianca's water debit is only 60g/10sec max.
The flow rate of the IMS B66 basket should be equal to or even slightly faster than it of the VST basket. I also use IMS B66 H26M on my Rossa PG.

Peter_SVK wrote:The question is not entirely clear to me (I'm not native english): ZP mark (or 0 on the scale, if aligned with ZP) is for orientation only, to do not touch the burrs accidentally, so if ZP is not equal to 0 on the scale (0-scale is not aligned with ZP, not calibrated), it's good to know, where on the scale the ZP is. If the scale and arrow pointer are both fixed (sticked to the grinder or engraved), there is no way to re-calibrate the grinder w/o removing/replacing the scale or the arrow pointer for new (changed) burrs.

Thanks, so numerical settings are irrelevant when changing burrs, it's just offset from ZP/burr touch.

Why irrelevant? There is certain offset from 0-scale to ZP (let's say 0.5 in my case), which is considered (added or subtracked) from actual position to get absolute setting. And absolute setting can be also calculated to gap between the burrs. Example: if abs. setting is let's say 50 marks (5.0 on the scale) and each mark equals e.g. to 0.01mm, actual gap between the burrs is 50 x 0.01 = 0.50mm.

We're saying the same thing, except that I'm saying the offset is different for different burrs so the absolute number is irrelevant, only the delta number.

So OK, that's wasn't cler to me from previous post. However, I think offset up to 0.5 (5 small marks out of 10 between numbers) is negligible and I consider it as very very good after burrs swapping (that means only 0.05mm difference between first and second set of burrs) and on par with some burrs (mis)alignment (my previous E65S). I also found 0.5 offset as conservative one, to early chirping, there is possible to tighten the burrs even more, up to 0.3.

James Hoffman posted a video on the lagom p64. He's doing the high end grinder show down every day this week so stay tuned.

http://www.youtube.com/watch?v=WeA-IqDEfMw

Did he confuse the burr sets? When he mentions the unimodal burrs he is showing the HU, and when he unscrews the burr set he has the unimodal burrs in.

I also noticed that.

It's likely to be an editing flub, he mentions in the comments that the HU burrs were used for the shot pulled in the video and the shout out.