NewtoEverything1,
to change only the skill you do not need to use vector variables nor vdn variables. on the vdn screen first page there are three fields: "1st Skill", "2nd Skill", "3rd Skill". if you set desired skill number in "1st Skill" field you can later use it in a vector, like that:
01 queue-to skill 1st priority m
02 wait-time 20 secs hearing music
03 goto step 1 if unconditionally
and for every vdn that calls this vector a different skill number may be used.
also don't forget that 1st/2nd/3rd skill numbers are affected by vdn override setting.