In general, the bigger the fish, the more risk during transport.
I've done a 2.25 hour drive with 9-10" HSB in bags with pure oxygen, and boxed. Out of (20) fish, I had one D.O.A. At the one pond where I put in (10) of these HSB, they had (4) morts within a week; I don't know if that was due to transport.
If you do some kind of DIY transport rig, I think you need pure O2, and not just ambient air; probably not as simple as one might expect.
