Hey Bob, I hear you when you're talking about the rpms this bike likes to sit at: maybe Kawasaki is cool with it, but the rider may not enjoy the sky-high revs! I get it, but I would really encourage you to try it a bit before you max out the tall gearing with sprockets. I found that these 250s excel in the 10k range and you have excellent passing power this way. Other things relative to that high rev-range; not only does the bike stay in the power band better, but I found the fuel economy was the same or slightly better with factory gearing as opposed to the taller aftermarket gearing. I think this has to do with loading the bike taking off from a stop. The last advantage to stock gearing is that it keeps the coolant moving at the rate Kawasaki designed it to. It really does keep the bike cool as opposed to lugging it around in "7th" gear.
Final thoughts: since 250s are extremely low hp engines, maxing out the gearing can actually make 6th virtually unusable unless you're going downhill. Theoretically, you have a higher top speed at lower rpms, but it's often the case that 25-30hp just can't turn those rpms at that mathematical speed. This is actually exagerated with high hp machines like the 1st gen Hayabusa: it was said those bikes had a higher top speed in 5th than 6th suggesting that it was over-geared. I get that this is not your concern, but something to think about. It seems a little mechanically cluttered to take your bike and make a 5 speed out of it
ALL OF THIS TO SAY 1 tooth on the front is perfectly fine and I've done it myself on many bikes. I would just steer clear of adding multiple to the front while dropping 3 on the rear etc. just to lower your rpms as much as possible. Either way, it will be fun to ride.