Full respect for your general experience mate, but (as you said) this is just about several similar engines and some of the really relevant factors re: belt run on this engine haven't even been touched upon.
With regard to the 2V engines, I agree with you Chris, about the rocker spring strength..........they can be a pig to refit..............but once in place, their effect on the cam position is minimal, just enough to push the cam off-lobe............. .......moving it back requires very liitle finger pressure on the pulley and you can actually 'balance' it so that it doesn't move when all the timing marks are lined up..................although you can't be complacent that it hasn't moved. Once the belt is in position on it's pulleys, it stops the spring from tipping the cam off-lobe and keeps it 'balanced' therefore there is no spring pressure as such on the belt.