coanda vacuum pump

Hi everyone,
I'm trying to make a conada based vacuum pump to be used in a machine shop to empty coolant tanks.
Something like this: https://www.youtube.com/watch?v=oADsdCdnddw
So far I've achieved some good results by experimenting with different venturi geometries but the max I can achieve is -0.2bar vacuum with no indication of the flow rate, and it works only with a short hose, 1.5m max on a 55gal barrel. My aim would be to get it to -0.5bar and at least 3m hose.
Been experimenting with it for months now and it is impossible to predict the most optimal geometry for the maximum performance because it seems even the slightest deviations have a drastic effect on vacuum formation and so on.
The only way I could get it right is to do flow simulation but had no success in getting the right results neither on mass flow visualization nor on the pressure difference.
Could anyone give some dort of advice on this little project of mine?
I'll attach a model of the best of what I've managed to achieve, but far from perfect, and a simple drawing with the basic info.
Thank you all,