I'm pondering the same concept.
I'd like to get at least 1 hour of additional fuel, 10 gallons would be nice. I'm leaning heavily to the Smoke System setup working to decide on whether the 4.5gal tanks are enough or should I just go to the 7.5gal tanks to get about 1:30 in additional range.
I have a local guy that picked up an 7A recently that has the system installed, planning to jump over and check out his system to get an understanding of the amount of room they take up.
Anyone that has gone down this path and has info, please share.
I installed TWO of them. The can be configured as 7.5 for 100LL and 7.5 for smoke oil OR 15 for either 100LL of smoke oil.
I did a video on it ages ago and will share the link if you think it might be valuable. Will have to go dig it up from somewhere.
If you could share the video that would be so helpful. Trying not to reinvent the wheel here so any install details would help a lot!
I did the video in response to a question that I had received from someone a while back regarding the tanks and external filler. Obviously it CAN be done but the hose will be more AFT and get in the way of baggage.
Also, you will note that I paid to have EXTRA "bungs" (??) so that the tanks could be vented, joined together, symmetric, and sight-gauged.
Here it is:
https://photos.app.goo.gl/JwiZq1Ap9wGBTb4KA
Thank you very much for sharing, helps me get a good understanding of the space, placement and plumbing.