Infill setting for functional parts (Decker 380)

So I'm doing a decker and it specifies 10 walls and 98% infill. Now I believe 100% is just essentially rectilinear right? Should I just do rectilinear for speed at 98% or does it matter? Like at 98% is gyroid even actually a gyroid?

Also while I'm asking, should I be using randomized seam or just keep it default?

.4 nozzle btw