I don’t want to beat a dead horse here Greg and I know you want an SV650 badly:) The issue is not HOW responsible you are as a beginner….and for the record I believe you’re a responsible guy!
The issue regarding beginner riders is about mitigating and minimizing mistakes. Responsible as you might be and as sure as the sun will rise tomorrow, you’re still gonna make mistakes. Your safety and your GF’s safety will depend on your ability to keep those mistakes within a manageable margin. If you can’t there gonna be consequences. When speed goes up the margin of maintaining a low risk of mistakes goes down exponentially.
I rode a friends Gladius this weekend and I’ll agree with you those bikes are a ton of fun to ride. Suzuki even touts those things as “entry level” sport bikes. Still if I had a friend who was just starting to ride that bike would not be on my suggested beginners bike list.
As always just my two cents worth
PS: Where are you in SoCal??