I run Spidertrax 1.25" hub-adapter style spacers. This gives an overall effective backspacing of 3.75" on 16x8 wheels, which is equivalent to the most popular 15x8 wheels used for 35x12.5. It works very well for my application, and I have had zero issues with this setup.
Running without spacers might be possible, but you would need to check very carefully for rub on the rear spring perches on the frame, and possibly add washers to your steering stops.
If you go with spacers, I highly recommend not cheaping out. I went with Spidertrax due to their use of appropriate materials, as well as the fact they are hub-centric. I would NOT use cheap spacers like the 5-8 letter all capital name brands you find on Amazon. When they fail, you lose the entire wheel, causing you to lose control and also send a speeding tire loose down the freeway.
Also importantly, spacers should not be used with wheels that are already low backspacing, since both of those add stress to the ball joints and steering knuckle. Generally, backspacing minus spacer thickness should not be less than 3.75" total for any 8" wide rim.