If youre putting the ring in the middle position, why not take an old outer, grind off the teeth, then run that as a sort of guard, plus means you dont need to buy any more bolts, ie shorter for a single ring.
Donkeys ago(about 97, i built a lightweight all alloy runabout, with a 1x8 set up. Did as above and used a ground down outer. All worked fine.
I think using the middle position helps run through more of the gears with a lesser chain angle than if placed on the outer position. Less chance if it picking up and chucking the chain off the ring.