I think it's 12 million being sold in the final stage - although by the time some are sold in private deals it may well be down to 2 million for ordinary players.
I think you might be right that selling vouchers and buying them from the secondary market works if you're only buying a few packs, possibly.
The perks you get for taking part in the pre-sale are only worth it if you're going in hard - like really hard - I actually bought 650 VOUCHER to take my drop up to 1000, although I only had to buy around 850 packs as the bonus ones for a bulk purchase took me up to 1000.
It may sound crazy, but with the extra SPS drop I get for the title and holding the packs and the guaranteed GLF and the regular promo cards and the extra chance of getting the future airdropped cards ("like they did with Yodin etc) and selling off most of the rest of my vouchers then believe it or not spending around $6K early on VOUCHER makes it worthwhile.
But unless you are literally spending several thousand (like over $5K) you're probably not going to benefit from the perks.
With the land purchase you had to spend around $1K for a tract, which conferred significant benefits now it's 5-10 times that, otherwise just get whatever you can as cheap as you can is I think the way this works.
The saddest thing about this game is that what I regard as 'going in hard' - I'm probably going to spend $10K all in on Chaos packs - Aggy wouldn't even give me the time of day for that kind of investment, I'm firmly in the 'pleb investors' category even with that.
I was going to go 'hard' with 7k US$...
Well, I just want the packs, and perhaps open some, to at least advance a league...
I just want to play a little bit for the fun of it and to understand it better as an investment. The title is out of the question for me.
Whether it be 5 or 12 mio packs is quite an important information and the explanations around it on splinterlands.com are pretty weak.