The label for eBay Standard Envelope comes in only one size (4x6). Cut and paste the label for smaller envelopes or scale just a tad.
Shipping - eBay standard envelope label dimensioned
Below is how I apply the label to a #10 envelope (it may have scaled a bit). Notice that the FIM bars at the top are where they are supposed to be, but the the bottom barcode is not. Sellers shipping in larger mailers have stated that labels placed in the middle of the envelope, not following any of the USPS placement directives, arrived just fine.
Shipping - eBay standard envelope
These are the USPS placement specs for letters:
Shipping - eBay First Class Letter
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