The geometry need to maintain is different from that of a conventional joint driveline. The cost differential is minimal and the performance/life gain will pay for itself in the long run.
Another factor seldom considered is the vibrations which will be caused by the forces required for acceleration & deceleration of the mass of your driveline. A driveline which is too heavy and /or having radius which is too large along with running through a steep angle can accentuate a problem here.
Also, you need to know your "U" joint life expectancy. Basically a "U" joint is rated for specific, continuous operating load @ 3000 R.P.M. for 5000 hrs. with a 3 degree joint angle, and assuming proper periodic maintenance. If you double the angle you halve the life, halve the load & double the life and vice/versa.
Where your driveline seldom sees a constant load, "U" joint life becomes a difficult number to crunch. While 5000 hrs. may not seem like much it's roughly equal to driving 8 hours a day, 5 days a week for 2& 1/2 years. So 20% of life expectancy may not be such a bad number after all.
Most drive shafts will, depending on components used, incur a binding interference at about 30 degrees. You DO NOT , I repeat DO NOT want to run a drive shaft at any where near this angle. you need to allow for axle droop, frame flexing and differential roll.
All of which can momentarily alter the operating angle of the "U " joint to the point that it will cause what I refer to as an IMMEDIATE & CATASTROPHIC FAILURE. Ultimately you need to be certain that your driveline will rotate freely under full axle droop.
It is also very important that you consider the upward pinion movement, caused by spring wrap, on the differential under high torque situations. You can usually get a pretty good idea of how much the differential will roll up with the following simple test:
After making certain that all of your power train is in good working order, and while standing a safe distance to the side of the vehicle where you can watch the motion of the differential. Have a partner set the park/emergency brake , start the vehicle, put transfer-case in low range, the transmission in 1st.
gear and accelerate the engine moderately. I think it may well surprise you how much spring wrap you actually have. Again it may be necessary to do something to control the upward motion of the pinion to prevent driveline binding and that big CRUNCH/SNAP which often occurs in high torque situations.