I’m very late to this part, but a more obvious source for the grade idea (and even the names of the grades) is the Dr Who story “The Sunmakers.” That was written by Robert Holmes; Chris Boucher had written the previous story, “Image of the Fendhal,” and I can easily imagine him watching other Dr Who stories.

It's brimming with ideas, it added at least 4 major things to B7 lore: Terra Nostra, Federation class system, Shadow drug and Cally's Moon Disk (that's an example of a non-humanoid alien, by the way, and it captured imagination of many viewers :)).

Also, everyone is so pretty in it! June Hudson's outfits are especially stunning and flamboyant in Shadow. Oh yeah Jenna's silver boots! And Avon's silver tunic – I thought he looked like a prince. Also he wears outrageous thigh-high boots but they are not in focus enough, sadly: blink and you miss it. Here are screencaps. 🙂
http://static.diary.ru/userdir/5/5/1/9/551988/85636265.jpg
http://static.diary.ru/userdir/5/5/1/9/551988/85636264.jpg

Vila is really great in this! Was so happy for him living his dream despite Blake's party-pooping. Also him calling out Blake as a middle-class revolutionary was fascinating, as were his comments about class system.

AndrewP mentioned grade system in Huxley's "Brave New World" – I didn't realize it was inspired by it! Didn't read the book but the Wiki page offered an insight into that system (eugenics, rigid castes Alpha through Epsilon based on intelligence ratings) and also this fascinating quote:

"Any residual unhappiness is resolved by an antidepressant and hallucinogenic drug called soma."

Soma is a drug in B7 universe too, though its effects are more medicinal.
B7 grade system also doesn't have to be exact replica of "Brave New World" but it's left open to interpretation. Maybe grades were assigned on tests like 11yr olds exams, maybe they were hereditary. Similar grade system was also mentioned in "Sun Makers" in Doctor Who.

Gan's developing a personality – a bit late, true, but at least it was consistent throughout S2. I wish they thought about it earlier, as he went from someone vaguely enjoying violence in S1 to an Everyman and a voice of common sense and decency in S2. But I liked his S2 development.

Avon, Bek and Hanna conversation in the holding cell – ohh, it was interesting, isn't it? Avon felt on the same wavelength with those two, fitting in their criminal world. And yes, interesting about him enjoying physical fight.

Also, to your question on where did Avon get the ID of the President's personal guard: my guess was that those fat silver-wrapped guards on the planet were from President's personal guard, and Avon got their IDs after killing them.

Avon not being quite human – loved his line about Cally: "She's more human than I am". Can be read in so many ways. And yes, he worried about her and understood that Blake was being so mean and shouty because he was worried too.
And oh – poor hungover Vila, yes! With Blake shouting at him like that.

The overall plot – agree that it doesn't hang together well, it's a collection of jumbled pieces, some of which are very good, like Cally threatening Space City; Avon, Jenna and Blake confronting Largo etc.

Ah, about Largo's outfit (and the Enforcer's): it reminded me vaguely of medieval Italy.

Love the other points you raise. For me, I recall that the 'grade' notion linked in with a US TV mini-series of "Brave New World" which BBC1 aired in early 1981. "Pushers" *was* a term which was in usage by then – certainly I was aware of it from the media and its use in other contemporary drama by the late 1970s. Jenna *is* the nicest smuggler you could wish to deal with – you get the impression that she'd give discounts and cashback. And Chris Boucher *does* have an awful lot of delight in writing for Avon – a factor enhanced in a performance from Paul Darrow who now knows how to fully exploit the character in the best possible way.

Thanks again – much appreciated!

Andrew