Hmm. It's a pity that it would be so hard to provide a neutral and sensible model for the rest of the kingdom and the rest of the gameplay, but it would be fascinating to see a simulation of how opening Page+Guide and picking up Masquerade/Ambassador after first shuffle compared with opening Page+Masq/Amb and picking up Guide after the first shuffle.
The back of my envelope suggests that Guide saves you about 0.75 turns per shuffle, so buying it before the first shuffle gets you Champion 0.75 turns sooner. And having Champion in play can give you an extra play of Masq/Amb each turn so in the long run you're only costing yourself 0.25 of a play of Masq/Amb by buying Guide on T1/T2.
I'm pretty sure that holds for Masquerade, anyway. Ambassador is more complicated, because:
- Thinning by two cards per play is a bigger deal than Masquerade's one.
- Getting a card via another player's Ambassador will hurt your advancement towards Champion; exchanging a card via another player's Masquerade doesn't.
- But conversely, with Ambassador out and about, getting to Champion ASAP is all the more important