Parts Guru's idea seems good.
We have a couple of dedicated PDI techs so its not usually a problem for us.
However, we do a large fleet business (900-1200 unit per year) so for 3-4 months each years we're deluged with PDIs. We throw that overflow work open to any regular line techs who are willing to stay late or work Saturdays

Funny thing I've noticed over the years: all too often the techs who complain about "not getting enough hours" never wanna stay late to knock out a few easy PDIs. The techs who quietly go about their work without complaining always seem to be more than happy to put in a few extra hours to sop up the gravy. Weird, huh ?
"Gotta make hay while the sun is shining"
Cheers
DD