What is the best way to randomize a selection of minted NFTs in Solidity?

Question

I want to randomize how different levels of NFTs are minted. If there are 3333 in total and 20 Tier 1 (being the best), 313 Tier 2, 1200 Tier 3 and 1800 Tier 4, does the following code do the trick? Could this result in the Tier 1 NFTS being minted every other 4 mints?

function _genTier(uint256 seed) internal view returns (uint256) {
        uint256 index = seed % probabilities.length;
        uint256 rarity = seed.mul(100).div(MAX_SUPPLY);
        if(rarity < probabilities[index]) {
        rarity = index;
    } else {
        rarity = aliases[index];
    }

    return rarity;
}