To figure out the windlass power you need the formula is [ 3X (anchor weight + total chain weight + anchor rode weight) ]
I believe the 65lb anchor is a tad over kill. For your size boat a new generation anchor, Ronca, Mantus or Mason Supreme, 36lb anchor should be plenty.
With that in consideration
3 X (36 + (150' 5/15chain=166lbs) + (100' anchor rode= approx 13lbs) = 645 lbs max pull.
Therefore a 1000 watt windlass would work great.
Like TQA I like the Maxwell RC10-8.
Hope that helps.