What I meant to say is that instead of
playing a $1 8/5 JOB machine (very common at Caesars now) at max
coins I've noticed players at $5 9/6 machines using one coin.
So, this got me thinking about which gives a better return. $1 8/5 playing full coins gives 97.29% return, a hit of 2.25% vs. full pay. Playing a single coin in a $5 9/6 machine gives a 98.18% return. So, it would seem that if your bankroll supported playing $5 a hand, a single coin on a $5 9/6 is a better play than full coin on a $1 8/5 machine.
But I wouldn't use that strategy personally because I know how
humiliated I would feel at losing $18750 by not betting the other $20
that hand.
I'm not sure that's the right way to consider it. If you were playing full coin on a $1 machine, a royal would pay $4000. If you're playing a single coin on a $5 machine, a royal pays $1250. That seems like a "loss" of $2750, not $18,750. Further, in the 40,000 hands you played to hit that royal, you would have hit 465 full houses and 445 flushes, and you would have won an extra $4550, more than making up for the loss on the royal. And, the odds of actually hitting those 900 full houses and flushes after 40K hands, or at least a significant fraction of them, are better than having hit the one royal.
Of course, if you bankroll supports full coin $5 play, that's better still.