This is a discussion that I intended to stay out of.
FWIW, we set our poles at 10% of the pole height plus two feet. A 45' pole would be set 6 1/2 feet deep.
If the soil is not heavy so we can tamp the butt solid, we will backfill around the pole with #53 crushed stone. We also use #53 crushed stone around most of our main line distribution and the transmission poles.
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Charlie Eldridge, Indianapolis,
Utility Power Guy