For DIY yourself baiting, 5 hours would be my limit. Where I live and hunt these days it takes me about 4 hours to get to where I'm going. The issue in MI is I seem to recall you can only use a Barrell on private ground. If that is still the case, I don't see how you could keep your bait going without the barrel (on public ground) unless you paid a Yooper to bait your site once it starts getting hit.
The other option you might want to try is reaching out to someone that already has an established bait site but doesn't have a tag. Many times they just want to keep it going until they, or someone else they know draws. It's a positive for you, and them in that scenario. Especially since its taking longer and longer to draw. I would really look into that option.