Launch OpenIV
Go to GTA5/mods/x64v.rpf/models/cdimages/streamedpeds_players.rpf/player_one

And replace this files

For Models (from any "Average" or "Beefy" or "Slim" folder)

lowr_018_r.ydd
uppr_026_r.ydd

For Textures (from any Set "1" or "2" or "3" and "For Torso" folders) 

lowr_diff_018_a_bla.ytd
lowr_diff_018_b_bla.ytd
lowr_diff_018_c_bla.ytd
lowr_diff_018_d_bla.ytd
lowr_diff_018_e_bla.ytd
lowr_diff_018_f_bla.ytd

uppr_diff_026_a_bla.ytd

UNINSTALLATION - in reverse order by replacing with backups.