Well ive done my research and decided to order the m-5 for my 3.5gpm 4000psi pressure washer. the only answer i havent been able to find is wheather i should go with #13 rated for 3000-4000psi or the #16 rated for 4000-5000psi? since my unit is rated in between both im not sure what the advantages would be. i read somewhere that a larger orfice would allow it to spray further/higher, so im thinking i should lean toward the #16. any advice?