Hello -
Welcome to FT.
May I suggest that you may wish to ask this question in the AmEx forum? It's under FT Miles, just like MilesBuzz!, just scroll down about 3/4ths of the way down the page.
However, I'll give you my thoughts anyway. The AmEx -> Starwood conversion rate is terrible, so I wouldn't go that route unless you really need the points.
You said you fly Delta, so why not just transfer your MR points directly to Delta on a 1:1 basis?
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