PK,
Considering the output of SNP heuristic you are creating just STRs. The same could be achieved in CTM and more or less you need same master data what you need in SNP heuristic. So not sure when you say;
But i wonder the complexity in maintaining master data and handling CTM planning engine might be complicated.
At least in your case you will be able to meet your requirement of demand prioritization which would finally generate STR. Thereafter you can do deployment.
So in CTM also you don't need below if you are not doing any produciton etc.
Also we are not using resource of any category (Production, Transport, Shipping or Handling).
I would recommend you to go through the below links to understand CTM and decide right solution for your requirement.
Multilevel Supply and Demand Matching (SDM) - SAP Library
Comparison of the Planning Methods - Supply Network Planning Run - SAP Library
I am sure handling CTM engine would be much more easier then creating a complex solution.
Regards
Rahul