If theres a specific card that you want to add to your deck, you can usually buy it from online markets or gaming stores
But given the nature of the card, dead late, terrifying early, it's a no-brainer that 3 would still be the preferred number if legal
To be honest, there should be another way of getting Lux out as well, though
Promos (P) Promotional cards - like the aforementioned Lightning Bolt from MagicFest - can come from events, prereleases, special products, store promos, conventions, Secret Lair drops, and various other places where Wizards know we players are willing to pay top dollar for them
Shipping Times We also have the best turnaround in the industry
The short version of this is Etali, doing Etali things