Looks like you're about up to Honda Rebel, 234cc of raging fury, speeds LOL. Maybe we ought to go ridin' sometime.

 

No handling issues at higher speeds. Maybe you are tensing up or just experiencing wind movement. You'll get used to that. I have been to 115 mph and had no handling issues with my Sporty. The Sportster model is the most nimble and easy handling bikes in the Harley line. That being said, and Electra Glide with it's extra weight and windshield likely does not blow around as much. (just guessing, never rode one)

 

Sounds like you're tensing up. Give it time, those speeds will seem like nothing.

On NJ highways, I'm usually doing about 75-80. All the family men driving their mini-vans seem rather jealous as I pass them up.

 

Relax, Relax Relax ----easier said than done sometimes. Whenever safe to do so just try to shake out your hands, open your hands & flex your fingers. Some times just readjusting your hands on your grips when you feel tense will help because you're tightening your grip without noticing. Try to not ride beyond your experience/skills/nerve and just enjoy the ride. Find a friend or group to ride with as that sometimes will give you more confidence as you watch the lines other riders take and usually you'll feel safer as well (safety in numbers)
Again welcome to the madness that is riding and have fun.