Shimanami Kaido luggage delivery

Hi all! Am considering to do the Shimano Kaido after Hiroshima in June, and am wondering what is the most convenient/cost-efficient way to get my luggage delivered across the Shimano Kaido while I'm cycling.

Here's a rough sketch of my itinerary: Osaka - Hiroshima - onomichi -omishima (stay over for a night) - imabari - kobe/okayama - osaka.

Will be getting the 5-days kansai hiroshima area pass since it's only 13,000 yen, as a one-way trip from osaka to hiroshima alone costs 12,000 yen.

I'm thinking of delivering my luggage from onomichi to imabari/kobe/okayama. I'm not staying overnight in imabari, but immediately taking a train from imabari to kobe/okayama after we are done with our cycling. Here are my options: 1. Get my hotel to deliver/arrange delivery for the luggage; 2. Go to convenience store to delivery by Takkyubin (how long in advance do I have to do this? I'll need my luggage to be delivered within 2/3 days' time depending on destination which I have yet to decide) ;3. Get delivery service at JR Onomichi station ( info from http://visithiroshima.net/special/bicycle_hiroshima_day01.html);4. Stop at Okayama before I head to Hiroshima, leave luggage and get it on way back to Osaka (as recommended by someone in https://www.reddit.com/r/JapanTravel/comments/3hj8u0/shimanami_kaido_l...). This however seems a bit silly as I'll be without my luggage for 4 days or so, defeating the purpose of travelling light for the cycling trip.

Would greatly appreciate it if anyone can provide me with info of any sort. Feel free to give me opinions on how I can do my trip better as well, as I'm open to suggestions. Thank you for taking the time to read!