Yes, I have 3-5gal jugs, now. That's how I've managed it for years. I always come up short, and have typically bought gas at the track..I never really thought that much about it. However, the 1.6 clearly performs better on 93 pump gas vs. the 91 pure gas. And 93 pump gas is a good bit cheaper than the 91 track gas, anyway. Sort of a win-win.
So, I either need to buy 2 more 5g jugs at $25 ea and ideally a couple of jug racks to hold them securely (versus my haphazard rachet straps), or possible a 20-30g tank that can fit on the tongue (or anywhere else on the trailer). There are several 20-30g "above board" tanks available in the $100 range. So, the cost factor is about the same.
The safety factor can't be any worse than the 5 canisters strapped to the trailer deck. Something securely nestled in the tongue triangle might arguably be safer in a practical sense (laws notwithstanding).
I'm all about KISS. But, 4 (or 5, or 10) separate jugs isn't necessarily simpler (or safer) that a single, large, permanently fixed tank. Its not even clearly cheaper. I still need a couple of jugs for pump-out and transfer, but those can be transported dry in the trunk of the Miata if I have 30g in a tank.
What I'm really trying to do is somewhat optimize my race operations, so that I'm not spending a ton of time getting ready for a race and then dismantling things post-race, or wasting mental cycles at the track figuring what I need. Process improvements, as it were.