On point one, just check the for sale forum rules.
On point two, if you don't find much difference and are of the view that the 307 is the pinnacle minus the window dressing, then you are very very lucky (I have the 307 and quite like it, but the pinnacle it is not, to me at least). Though not sure why you ordered the bhse if you are building all these other amps that you are unlikely to discern any difference with.
Ah the forum, saving us from ourselves.
On two I should say it differently, I mean that I see the lowly 307 as like an athlete getting the bronze metal. The 009/BHSE/whatever gets you to the gold. What's the difference between an olympic gold and bronze? A few milliseconds usually. Otherwise I said it above, I'm getting the top because it's not that insanely priced (compared to speaker-land) and, why not?