Re: 5 1/4" baseboard molding with 97 degree angle
If this is an inside corner, then you can run one side long into the corner then cope the companion side. For an outside miter, put the end being cut against the fence and shim the tail end away from the fence and make practice cuts on scrap until you get the complimentary angle for both cuts. to make this cut you'd be cutting back to front, so you'll want to use a backer to minimize tear out on the face of the trim.
Most newer chop saws will cut to 47-1/2 degrees, which is close to what you need. I'd start with that and see how the fit is, then work from there.
It just occurred to me that with the size of the base you're using, you may need to cut the pieces laying flat rather than standing up. Same techniques will apply, only the orientation of the material in the saw will change.
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