I'm what you'd consider a new owner, so here's my "new owner" input!
I have 16/40 stock gearing. I'll keep it until I can ride someone's RC that has a different setup so I can compare. I don't have the means to just start buying and swapping around different sprockets until I figure out how I like it. I love my stock gas mileage, and that'll take a crap if I change that gearing. Off topic...I've only had the bike stall when I didn't have enough gas into 1st gear or I let the clutch out with the kickstand still down. I don't have any issues coming to stops with it. There's another guy over at Speedzilla (unless it's you under a different name) with the same problem it seems. Go here
I have to use it any time the engine is cold. Whether it's 65 F in the morning or after the bike has been in the sun all day in 85 F. If I don't have it pulled when I start the bike, it will die. I don't leave it engaged for any longer than 15 - 30 seconds.
This is my first motorcycle with a temperature readout. With my previous motorcycle ('09 650R) I'd let it idle for about two minutes. With the RC, I haven't timed it, but I think it takes a little less than that for it to show 110-115 F. I'll ride it after it hits 120 F.
I just run the stock HP Pro Coolant without any additives and the hottest I've gotten is to 222 F in town. The fans kick in and it scoots right back down to about 208. On an average 55-65 MPH ride in 4th gear it stays around 185-190 F.
Haven't had any problems to diagnose yet.
I always run premium, which in my area is 91 octane with 10% ethanol blended. I've had no issues with it, but I try to get my fuel from Kwik Trip gas stations as their premium fuel is "Hobby grade" and doesn't contain ethanol.
-Based on the age of my bike (2004) and the fact that my previous owner had no service orders for the bike I had to assume most essential fluids and such needed replacement. Unless the previous owner can confirm maintenance, at minimum I'd give yourself a maintenance baseline with an oil change, coolant drain/replace, and flush the brake fluid out of all three reservoirs. I'm not the most mechanically savvy guy, but I did all of it myself and saved a bunch of money. No leaks or anything, I was impressed! Only thing I was a little leery of was that on the coolant drain it didn't completely drain out both radiators. Not sure how someone is suppose to cycle out the rest of the rest of the fluid. I started the bike but nothing else came out the bypass hose.
-If you bleed your own brakes and clutch, DO NOT
use the factory manual torque specifications! 6.5 ft-lbs is WAY TOO much for the bleeder on the clutch slave! I started torquing at that rate and was like, "Holy sh*t if I keep going this thin is gonna strip!" Just tighten 'em until they fluid doesn't run out anymore.