The one from Valley Vapour also says Model SF-830 on the box. Presume it is the same thing.Thanks very much for the offer @Polar but I'll order an SF-830 from Blck and see how it goes. I don't mind the jumping to 0.04 on the second drop - as long as it does jump and doesn't stay stuck on 0.00 when I've already done five or six drops. I have a 500g 0.1g MH to use in the meantime although that doesn't register anything below 0.3g. I was quite impressed with how accurate it is, though. I got my calibration weight yesterday and checked it today - it shows 199.8g for the 200g weight, which is easily near enough. Especially considering that I make a number of Wayne's recipes where I use 1.036g per ml of concentrate and Wayne himself just uses 1. And even my 1.036 is rough, some are more, some less. As long as it's in the ballpark, it's all good.
Has been working well for me. Now and then it freezes, like you mention. This always happens with small volumes. What I now do is to use the Tare function as little as possible and just add up in my head as I go along.