I'll throw in my 2? ($1?) here.
'08 w/ABS. 25k miles. Came to ST13 last Aug after years with GL1200 and then a GL1500 - talk about different! GLs have tractor engines - pull from <1K rpm.
I run 91 oct NON-ethanol gas (highest octane you can get short of AvGas at this altitude ~5000 ft. This also cause about 15% HP drop compared to sea level :-(). The "pure" gas at 91 oct gives me no indication of predetonation knock at hard acceleration above 2500 rpm. I'm 188, and about 206 with all gear on. Wife is probably(??) about 155-160 with gear, as point of reference.
With that...
Following info is for solo riding. Two-up riding - take the following numbers for shift rpms and add 500 or so.
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I tend to be fairly conservative during most riding, and almost 100% conservative/economy minded around town (twist the grip a good one and you're at 40 in 1st in about 1? sec - speed limit 25.)
I don't watch it anymore (go by feel/sound) but I'd say my upshifts are typically in the 2500 rpm range, but this is with GENTLE acceleration. Running around 25 mph (true spd) on surface streets is 2300 or so in 3rd, touch under 2k in fourth, but this is just maintaining speed, not accelerating. You definitely will get that "chuggle" / "box of rocks shaking" sound from the engine (don't think it is actual pre-det knocking - not distinct enough) if you give it much twist below 2k or so.
I have found (based on instantaneous mpg readout) you want to stay over 2k for optimal economy. Below that and the torque isn't there and it is really sucking the fuel. At the lower speeds, I would always choose to cruise >2k, and best economy seems to come about 2500 (excepting big headwinds, etc.). That equates to 3rd gear to 25-30ish, 4th gear to 30 - 40ish, and 5th above 40 (for cruising or very gentle acceleration).
As others mentioned the torque curve starts ramping up a bit past 3k and pulls real hard in that 4500 - 6000 range. If you need to get the "heck outta Dodge" the tach pointer better be in between those numbers on the dial. Holding shift past ~6K will not gain you any more acceleration (just more velocity), and the upshift will still put you into the upper 4000s which is still within the peak torque plateau.
My experience in running around town (not "racing") - 2nd gear is best for cornering and speed changes above ~10 mph. The throttle response is pretty choppy above those speeds in 1st (FI shutting off and on, engine braking, and FI surge when rolling on. Taller gear uses the bikes mass to dampen the response to those engine responses. My experience anyway.
I'll typically touch 4K before shift on interstate on ramps 30 to 75-80 (true speed , my speedo is 9% fast) in short order - some ramps around here are either pretty short or significantly uphill.
My bike is turning ~4150 (if I recall right) at 75 mph true (84 indicated) in 5th. I'll run that continuous all day without a worry in the world. The engine loves highway cruising in that 4k range. I notice very little vibes at that speed/rev. Not as smooth as the Wing-Tractor at 3500(?) at 75, but not at all bothersome.
Probably a bunch of restatement of others feedback, but hope it is of some guidance. I read all the previous posts to the thread, and I would say you probably don't have to be as aggressive as the average suggestion, but you're probably rolling around in the mud where you were trying to operate. The revs will only hurt your fuel economy. Staying south of extended cruise above 7000-7500, do regular service, and you will not hurt the engine. Shorten your service interval some if you routinely cruise above 5500 or so would be my suggestion.
Regards,