Well what you have is a mixed marriage of parts the task it to get them all to speak the same language LOL The driver that you have is a Comet 40 series that is to use a 7/8 inch wide belt and your driven half is a DEEPCO original to the Trooper. I would probably use a 5/8 inch wide belt. The Comet belts you listed are 20 series belts and are 3/4 inch wide. The two belts you have chosen are made for different center to center distances of 1 5/16 inch.
My suggestion is to find a belt from say Gates or Dayco that might be closer to what you need.
What is your center to center distance when you engine is in the middle of the adjustment slots ? I have had to do this on a tote gote I had.
Steve