Custom infill pattern?

What's the easiest way to add a custom infill pattern to my part model in CAD? I have a bridging section that will be pretty easy as long as I can control the infill direction, but it requires more control that what Orca will give me.

Like, I'm using a .8mm nozzle, so do I have to model a bunch of .82 mm extrusions into my part--kinda make it look like the extrusions do in the slicer graphic? My concern with that is, if I want to print this part with a .4mm nozzle, will I have to redraw all the extrusions to be .41mm wide?

If that's the case, can I model the extrusions as .41mm wide but still slice it for a .8mm nozzle and just expect the slicer to combine two .41mm lines into one .82 mm line?