If you want to leverage cheap spot, use us-east-2 / Ohio region. The prices are typically half of what you see in us-east-1.
Also, it really helps to analyze at the AZ level. Certain AZs lack instances or have very low spot availability and contrary to recommended best practice, reducing AZs can sometimes be beneficial (I am looking at you eu-central-1a).
While lowest price sounds nice, they can be really messy in terms of spot interruption rate. It is much better to set a max price and choose capacity optimized with as many instances as possible.
this actually depends on the region. amazon stopped randomizing az names in new regions quite awhile ago, while also offering azid as a guaranteed id in all regions.
Also, it really helps to analyze at the AZ level. Certain AZs lack instances or have very low spot availability and contrary to recommended best practice, reducing AZs can sometimes be beneficial (I am looking at you eu-central-1a).
While lowest price sounds nice, they can be really messy in terms of spot interruption rate. It is much better to set a max price and choose capacity optimized with as many instances as possible.