UVB should span the entire length of the cage, or at least 2/3rds of the cage. Basking light should be at one end, which produces a natural cooler end providing the basking isn't too hot or the cage too small.
For forelimb-less bearded dragon, I suggest a very low flat and wide basking spot. As he can't use his arms to climb up or down, a typical basking spot will prove impossible to navigate. Even with a wheeled harness, it may still be impossible for him to properly thermoregulate.
A wide flat basking area with the basking light hitting it slightly off center to provide warmer and cooler areas on the flat or very slightly sloping basking area, should work best. It will really depend on how mobile your dragon is without his front limbs. If he seems able to move about pretty freely, he may be able to handle ramps etc to get to higher locations. It will be something of trial and error. Try laying large flat rocks (such as slate tiles, ceramic tiles, shale, etc) or wood underneath the basking light. Sanding down the ends so they are easier for the dragon to get over is good, or adding a mini ramp to the shale (or carefully cutting or chipping off the corner, then sanding it down to take the sharpness off) will work.
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PHLdyPayne