It just takes a long time. Probably 8 sessions per quarter star. I'm sure with a good combo of partners you can get it down to 6 or so, 500k cuts it down another couple sparring sessions.
I've tried, seriously. My other camp, which is now dying but still able to make money when I do log on, tries to train up over 2.75 and can't. It won't even give 1 good message, they're all bad. So it leads me to believe it's impossible, if not just down right unable.
I think about 4 sessions, once, all horrible training sessions to try and get over the hurdle with a really good trainer and a good learner. It was just weird seeing that. I wouldn't risk that on my main camp unless the fighter was rounded enough that I could trust a couple of missed sessions, or unless I figured it was their only option to survive.
Might I recommend my approach to training?
Start keeping track in a log of who your guys train with, you will eventually see a pattern of who makes for good sparring partners for that individual and who doesn't. I like to have multiple guys as stat leaders so there are options for my fighters to spar with.
Anyways, here's one of my guys. Notice the trend of him training well with Denny Reinhold (granted he is a quick learner). It only took 4 sessions to get to 2.75 Flexibility with 50k equipment. I'll let you know how long it takes for 3.0 Flexibility;
Ben Wiltsie:
Reflexes: 2 x complete - Denny Reinhold (1.5)
Reflexes: 2 x complete - Denny Reinhold (1.75)
Reflexes: 2 x complete - Denny Reinhold (2.0)
Flexibility: 1 x complete - Denny Reinhold (2.25)
Flexibility: 3 x complete - Denny Reinhold (2.5)
Martial Arts: 3 x complete - Maurice Sherk (2.25)
Martial Arts: 5 x complete - Maurice Sherk (2.5)
Balance: 2 x complete - James Howard (2.25)
Balance: 3 x complete - Phil Bryant (2.5)
Speed: 2 x complete - Buddy Brooks (2.25)
Speed: 3 x complete - Buddy Brooks (2.5)
Footwork: 4 x complete - Sammy Ward (2.25)
Footwork: 3 x complete - Maurice Sherk (2.5)
Flexibility: 4 x complete - Denny Reinhold (2.75)