I don't think small as possible is the way to go with articles. Since this isn't a retrieve done at a run, the sizing is less critical. The articles are fine as long as they don't block vision, poke the dog's face, and the dog can pick it up without mashing their nose into the mat or ground. You'll eventually want multiple sets, so take the free set!
--Regina and the GSDs:
UCDX von Sontausen Holy Grail (The BUNNY!) HGH, UD,RA,BN,GN, ASCA UD RAX High in Trial
PAM Monster Mike SchH2,UDX,OM1,TD,RE,VER
PAM FGDCh Ianna von Sontausen UDX,BH,TD,RE,PT (4.26.1998 - 2.11.2013)