It is simple math, but requires actual weights of both TV and trailer. Axle weights of them both fully loaded
Here is the formula GCWR >= TV GVW + Trailer GVW + HITCH/Misc
You also need all of your RATINGs for both TV & Trailer...GCWR, GVWR, FGAWR, RGAWR...and do NOT go above ANY
Of course decide if you believe in the RATINGS system or not...the wheels will not instantly fall off if over...just sooner AND performance will be less that at or below your RATINGS
Performance includes braking and MANHANDLING the WHOLE setup...not just getting it going