Using 1/8 turn gives less clearance for the lifters to pump up. In most cases where the engine is equipped w/the right springs and the engine isn't over revved, there's no advantage over using 1/2 turn- which is what I (and your Dad) recommend you use.
The possible problem w/using a small preload or zero lashing the lifters is that it gives the chance for the lifter inner plunger to contact the retainer. Most lifters use round wire retainer clips (center and right, below); these can be driven out of their grooves allowing the lifter to come apart under severe conditions, like when the lifter pumps up. Lifters designed to be zero lashed and solid lifters will use an internal C-clip type retainer (below left).