@ Arzi. That depends on your playing style. If you are a light touch finger player you should be able to lower it a tad more.
When I set up for my customers, I get them to play their normal style and tweak the action until it is as low as it can go without the dreaded fret buzz.
On fretless, I actually like a slight amount of finger board buzz, it gives the Bass a nice warm sound.
Not easy to get right and requires the occasional tweak to maintain the vibe

@Pestybitz. Wot Pabs sed!
Get that Bass up a bit, whilst it looks cool to have it slung low it will lead to dramas later in life.
Also raise the neck angle so the headstock sits just above your elbow height or thereabouts...
AND STOP STRANGLING THAT NECK
You will never get fast if you are Gorilla gripping the neck!