Hey @jdr365, welcome to the FasCat Fam – we are stoked to have you!
As far as off season goes, we highly recommend the 32 week off season training plan & this is the ideal time to start. The 16 week resistance training + base is more geared towards someone who has not started off season/base training early enough.
To answer your question, yes. All of our plans can be done based on heart rate. Here is a thread where coach jake gives some tips on how to do that