I was annoyed when distance measuring devices became everyone's new toy; but the novelty wore off quickly and the pace of play returned to normal. I use chicken bones...three thigh bones to be precise. Just drop them on, or near, a known yardage and proceed from there. Give yourself a few yards plus or minus...works every time.
Whenever I play a provisional I use a colored ball. I drop one in my left front pocket, at the start of the round, and endeavor to have it remain there.