Thank you for your response.
I have tried parameterizing it by:
1) passing a parm in the EXEC, like PARM=('JP1"&PRM1"','JP2"&PRM2"') with two SETs:
// SET PRM1='abcdef'
// SET PRM2=42
OUTFIL BUILD=(JP1,1,JP2),REMOVECC,VTOF (it is not working)
2) with PRM2='1,42' (it doesn't get it)
3) with SYMNAMES:
//SYMNAMES DD *
The third solution works but since the files have each different length it means I will need many symbols and SYSINs anyway so there is no difference to coding them explicitly. So probably there is no other option but just do that.
It's strange I would think it should be easy to code...