Thank you, I think this will work for me.  ̶B̶u̶t̶ ̶i̶s̶ ̶t̶h̶e̶r̶e̶ ̶a̶ ̶n̶i̶c̶e̶r̶ ̶w̶a̶y̶ ̶t̶o̶ ̶s̶e̶t̶ ̶̶m̶.̶c̶u̶s̶t̶o̶m̶_̶v̶a̶l̶[̶0̶]̶̶ ̶h̶e̶r̶e̶?̶ ̶I̶ ̶c̶a̶n̶ ̶k̶e̶e̶p̶ ̶m̶y̶ ̶c̶u̶s̶t̶o̶m̶_̶v̶a̶l̶u̶e̶ ̶a̶s̶ ̶t̶h̶e̶ ̶f̶i̶r̶s̶t̶ ̶e̶l̶e̶m̶e̶n̶t̶ ̶b̶u̶t̶ ̶i̶s̶ ̶t̶h̶e̶r̶e̶ ̶a̶ ̶n̶i̶c̶e̶r̶ ̶w̶a̶y̶ ̶t̶o̶ ̶s̶e̶t̶ ̶t̶h̶i̶s̶ ̶s̶o̶ ̶t̶h̶a̶t̶ ̶i̶f̶ ̶̶c̶u̶s̶t̶o̶m̶_̶v̶a̶l̶u̶e̶̶ ̶i̶s̶n̶’̶t̶ ̶t̶h̶e̶ ̶f̶i̶r̶s̶t̶ ̶e̶l̶e̶m̶e̶n̶t̶,̶ ̶i̶t̶ ̶w̶o̶u̶l̶d̶ ̶s̶t̶i̶l̶l̶ ̶w̶o̶r̶k̶?̶
EDIT: My mistake. I thought this was to access to the first element of the model, instead of just a way to access the tensor value!