how to have worse quality like 0.5 and not draft 0.3?  

RE: how to have worse quality like 0.5 and not draft 0.3?

Hi Adam, 
If you have a Prusa Printer, you can use the Configuration wizard to enable the 0.8mm nozzle profiles... 

If you have a non prusa printer, and there is no 0.8mm profile, then you will need to configure a custom profile. 

off the top of my head, you need to :-
set the nozzle to 0.8mm in 'Printer settings > Extruder'
Set the Layer heights in 'Print settings > Layers and Perimeters' Maximum recommended layer height Less than or equal to 0.8 times Nozzle diameter  0.8mm nozzle X 0.8 = 0.64 mm. 
Set the Extrusion width to a value greater than or equal to the nozzle diameter, for all artifacts, other than supports, in 'Print Settings > Advanced' 

Note you may need to be in Advanced Mode, or Expert mode, to access some of these settings 

one of our members (Bobstro) has an information page, for larger nozzle configuration. 
https://muppetlabs.co/3dprinting_nozzle_sizes.html#guidelines-for-printing-with-different-nozzle-sizes
unfortunately it does not directly list 0.8mm nozzles. 
If you use '1.0mm nozzle' values for extrusion width,  you won't be a million miles away from a workable solution (Set the nozzle diameter to 0.8mm )
Regards Joan
or copy the values from a prusa printer profile...