I cruise around 65-70 on my 883. I added weight to the handlebars to knockdown any vibrations in them (a roll of nickels in each side). I have yet to ride it since the weight addition. I ll keep you posted on the results.
I had a 1200 Sporster before I got my Electra-Glide Classic. Look in the mirror when riding at different speeds. The better you can see, the better the ride. 55 was the worst spead to ride at and 60 was the best.