If it is chewing through UJ's I would suggest something else is wrong not just the heavy usage:
Is the current prop phased correctly?
Is there any play in the splines in the sliding section of the prop?
Does the sliding section actually slide correctly?
Is the yoke worn allowing the UJ cup to spin in the prop? (I currently have that with mine and and need to replace the prop)
Less likely but do you have lift kit fitted altering the pinions angle of the diff?
The other thing to bear in mind is UJ's are just not as good as they used to be, so unless you are fitting a good quality greaseable GKN (or equivalent) unit a UJ is not likely to last very long. My recorded was three weeks for a sealed for life no name UJ. A GKN one will last me about 2 years.