I went with Ssp cast and the Daniel Wong single dose mod although it was on my Super Jolly.

Very happy with the set up right now.

For me, it's been really great.

The work flow is a bit more work than other single dose grinders I would think, but for the price and frequency that I use it for, it's awesome!

My retention is less than .2g about 95% of the time. I usually get my dose out (15g) most of the time. Occasionally I'd get a 14.8, 14.9, which is still really good.

I use it for my French press and cold brew. I turn the dial 180 degrees from touching for french press and it works great.
Putting it back where is was previously works well and at times requires a small adjustment.

As for exchange, that, in my opinion, is a whole different topic thats really tough to prove or analyze.

I have not titled it forward, but know that people on here have done some really cool mods to their mazzers. Cut them to tilt, put variable speed regulators on them etc.

If you don't want to spend money, the doser works well for single dosing, but not as good as the DWS mod.

I can try to get some numbers from my other mazzer SJ with the doser for retebtion if you are interested. I'm sure that's been covered on here as well. I'd think it s around .5g or less honestly.

I usually run a bag of beans for single dosing, so switching beans every day or during the day is not a problem for me.

Let me.know if you need any other help.

Espresso parts had the single dosing mod for mazzer which was about the same price as the dws mod, but you had to wait for the 30% off offer. I'm not sure if they had one for the Major, but know they did for the SJ.

I'm using mine with the Wong conversion, a mini hopper and timer, SSP red speed burr set.

I must say I rarely need to adjust the grind, partly because I'm only doing espresso, yet when I change the grind in a more drastical way it takes a while to 'settle' down again.

All in all IMO a great grinder (beware of the break in period for the SSP burrs)!