I know that in EUII 1.09 (and so presumably in FTG):
"Each vassal a nation has now has reduces the stability and technology costs by 2%. This effect is capped at 20%."
Also, that this effect is reduced by high centralisation (0% benefit at 100% centralisation). For countries like Denmark, which often have lots of vassals (German minors etc.) this effect is quite important, so I'd like top understand it better. Does anyone know in more detail the effect centralisation has on vassal benefits to stab and tech costs? Does the relationship of the vassal of any effect (e.g. does it have to be >= 100?) on this? Is manpower affected at all, or am I just getting confused with the HRE bonus here? Thanks!