I have a similar one (cheap chinese version of the megabucks logic one) its an absolute bitch to try and set a good rate on. 2kg an acre of turnip seed is either 0.5kg an acre or 4kg an acre nothing inbetweenI tried rape and stubble turnip with one of those. Thought there was a lot of broken seeds.
Very fast though. Actually it got a lot faster at the end when the seed was running low
Took it apart did some bodgineering on it and it does 1kg to 3kg so its a bit hetter but not much
Just do the field twice works ok and was £1000 less than the logic
Will hopefully try some overseeding with it this year speed might he my friend on that one