Here is your AIO insert. Please let me know "L" and I will get this done for you. You can send your name and shipping address to [email protected]. No charge for this. Might take about a week But as an FYI, these will be available for sale from $65 to $95.I don't really know much about the design and placement of baffles, chamber sizes etc. But i did measure my tank height at 17 3/4" from the bottom glass to the plastic trim ring.
I did find this example from OceanBox Designs
The size you are getting will be priced at $75