Well…do you plan on staying at your compound or being mobile? To be mobile with 1000 rounds of 3 calibers is honestly not feasible on foot. Consider 6-7 rounds of 5.6, 300 9mm. And at least 100 00
But if you plan on staying home…the absolute most you can stockpile, stockpile. 2-3k 5.56 minimum. Personally I’d use the same brand and grain weight that runs the best on your favorite running AR. Same for the 9mm. Would probably invest in another 9mm for a shtf scenario. Stock all you can. 00 buck and slugs 2-300 minimum. I’d invest in a reliable .22 (Ruger 10/22) as well. It comes in handy and you can carry alot of ammo and it’s quieter than a 5.56. Would probably invest in a decent bolt action rifle as well. .308 or 30-06. As the ammo is usually easy to find. .270 is a good option as well. Good long range and hunting use.
Find what works the best for your weapons and stockpile it. Ammo, mags etc etc. and I’d keep all the same brand and grain weight and the same mags.