Is A1s still around?
So single item, either for individual or a set, right?
...
so for example:
Pressure Carapace Armor, a set for the group, base rarity (Very Rare), quality (Good). overall odds: 28% correct?
No, +30 is for an individual and could be more than one item. For example buying grenades or drugs would get you enough for one person to use. You'd effectively have an infinite amount of grenades, but if you let other people use them you'd mysteriously run out. Caellath already explained that you got the math wrong for a set for the group, +30 would be "Carapace Armor just for me".
You can also combine acquisitions to get more than one item, typically those that go together like a new gun with special ammo and mods. This is a -5 penalty for each new item and uses the highest rarity of all the items for rarity.
I'm thankful the annoying legwork rolls were taken out. They're a big part of why in many games acquisition-related matters usually end up with a single person who's familiar with the system doing all the math.
Could characters negotiate for other characters still? Maybe once for themselves, at least once for someone else? If the victim beneficiary accepts, of course. And do the extra maluses from the Core book's p.274 still count in face of BFK's updated component rarity chart?
And how many soldiers can we stick into the Dictator? And what does Dino cavalry count as, when it comes to BFK's army composition? I might wanna get lodes of warriors for totally peaceful purposes I swear.
Negotiate probably. It really isn't that big a bonus so I won't worry over it too much.
The 274 penalties are supposed to replace scale, the rarity chart replaces the rarity chart on page 207 in the Core Book. Well it expands it for more expensive components.
Dino Cavalry counts as Light/Medium/Heavy cavalry depending on what dinosaurs they're riding. Modern tech level. So you're probably only going to be able to afford a small force of them
. Individuals will fight using Only War's cavalry rules.
Dictator Crew: 100,000
15,000 Dedicated to Aircraft
68,000 Voidsmen
8,500 Armsmen
8,500 Combined officers and Warrant Officers.
Without dedicated storage space you could probably squeeze another 2000 men in. More if you replace existing (or non-existing) arms men with soldiers.
What'd be rarity for a ridable but compact dinosaur? Don't necessarily want to stomp around on a T-Rex but power and teeth would be good.
Rare for something like an Allosaurus, Very Rare for something like a T-Rex, Scarce for something like a hollywood style Utahraptor. Riding follows Only War rules (basically they act as a vehicle that uses Survival Tests)
EDIT
Since you're technically a Psyker you can also get a familiar, but it'd probably have to be smaller than rideable unless you go on some special sidequest or something.