Hi Michael,
I think that the speakers using the Lii Audio L15 probably sound very good. They might be a little rolled off in the highs and maybe not quite have the lower bass impact that I like but they are probably pleasantly balanced. At any rate, they should give you a good sense of the OB sound I would think.
I played around with the Lii Fast 8 for a while and it sounded very good especially for the price. Ultimately the Fast 8 did not go low enough for my application.
If I was still building speakers I would build a pair using the Lii L15, the Lii W15 (active) and a dipole planer or AMT up top. They would definitely not be shaped like a barrel.
The speakers I have now I built. They are similar to the ones shown in the link below to one of my YouTube videos but with a different driver compliant and made from wenge. The speakers in the video have a 10" coaxial in the middle with two 10" active woofers above and below. Mine have a BG NEO 8 PDR planer in the middle with Beyma 10" mids above and below in an MTM configuration. The top and bottom positions are still 10" active woofers woofers.
https://www.youtube.com/watch?v=5i85HpoGrpk&t=28s
Mike