Skyrmions are topologically protected vortex-like spin textures, and have been attracting increasing attention due to their potential technological applications for spintronics. In particular, metallic magnets with chiral and cubic/tetragonal crystal structure may have high potential to host skyrmions that can be driven by low electrical current excitation. Recently, the formation of skyrmions with unique spin helicity both at and above room temperature has been demonstrated in a family of cubic chiral magnets: beta-Mn-type Co-Zn-Mn alloys, which have a different chiral space group from that of the B20 compounds usually associated with Skyrmions. In this study, we wish to investigate how varying the stoichiometry, and therefore the strength of the exchange interaction, affects the Skyrmion phase, by looking for the signature of Skyrmion formation using transverse field muSR.