Anything over 26001 you need a cdl, or that is what Drivers facility told me. So I don't see what it gains you. J50 is good but you still have to take written and driving so might as well get a cdl.  

Vehicles Requiring a CDL

• Any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001 pounds or more, providing the Gross Vehicle Weight Rating (GVWR) of the vehicle being towed is in excess of 10,000 pounds.
• Any single vehicle with a GVWR of 26,001 pounds or more, or any such vehicle towing another not in excess of 10,000 pounds.
• Any vehicle, regardless of size, designed to transport 16 or more persons, including the driver.
• Any vehicle, regardless of size, required by federal regulations to be placarded while transporting hazardous materials.

Drivers Exempt From Obtaining a CDL

Under state and federal law, certain drivers are not subject to the requirements of the CDL program. The Federal Motor Carrier Safety Administration has determined these exemptions will not diminish the safe operation of commercial vehicles on the highways. Although the following vehicle operators are not required to obtain CDLs, they are required to hold the proper driver's license classification for the type of vehicles they are operating.

• Farm Equipment Operators — The farm operators' exemption is intended to cover legitimate farm-to-market operations by farmers, not commercial grain haulers.
  • Farm Vehicle Driver-FVD (J50 Restriction) — If the farmer, his spouse and their children, parents on both sides, brothers and sisters on both sides and their spouses are operating a truck-tractor semi-trailer combination or combinations, they are exempt from the CDL Program as a Farm Vehicle Driver (Non-CDL FVD). However, these drivers must be age 21, they must pass the required CDL written and skills testing and the vehicle must have Farm plates. A J50 restriction is required on a Class A Non-CDL to allow this operation. These drivers must also follow the restrictions listed below.
  • Covered Farm Vehicle Driver-CFV (J51 Restriction) — If a farmer, a family member or a farm employee is operating a truck-tractor semi-trailer combination or combinations as a Covered Farm Vehicle, they are exempt from the CDL Program as a Covered Farm Vehicle Driver (Non-CDL CFV). However, these drivers must be age 18, they must pass the required CDL written and skills testing and the vehicle must have Farm plates. A J51 restriction is required on a Class A Non-CDL to allow this operation. Drivers must be 18 to operate intrastate and 21 to operate interstate under this restriction. These drivers must also follow the other restrictions listed below.