Cheers Ian.
I don't recall seeing that measure the fuel method before. Bit of a pain to keep taking float chambers off, bending the clip, back on, fill with fuel, check the fuel height etc
Going back a few years here to use this quote.
The fuel level is the recommended way of measurement in the factory manual.
The carbs must be on the bike and the bike upright and level in the front to rear elevation. (as it would be in 90% of its operation)
The alternative is to use a jig on the bench to place the cabs at the angle they would be at on the bike.
The reason this method is recommended is because rapidly and at a glance the level may be checked by the service technician
without major disassembly.
If the levels are found to be significantly out of spec. it is at this point the carbs are removed and the float height method is then
utilised.
I hope this has clarified somewhat.
Many owners remove the carbs from the bike and attempt to bench set the fuel levels (as shown in a previous pic. although not intended I presume) with the carbs at a totally different angle to what they are when attached to the machine.
The fuel levels set thus can never be correct.