Wow. That's some intense maths you've done there. 😂
I decided to keep it simple rather than try and timing for buying vouchers/SPS. I'm going to wait until the end and buy packs in 100 intervals with the vouchers I've earned.
If it works out cheaper to buy with SPS to get the 10% discount I'll do that. (Although I haven't worked out the actual mechanics to do so yet). Or I'll just buy with Fiat.
Overall I want to use the presale as an opportunity to put more Fiat into the game.
Good luck with your plan!