Creating new ERC20 token and I'm in need to plan token vesting schedule for 24 month for different groups: private sale, public sale, team wallet and etc.

Does someone have experience and could advice me which way is better? To create vesting contract or use 3rd party vesting dApps? If I use vesting contract how do I get all wallets addresses in a contract (I mean there will be many private investors) and also how will they retrive those tokens? I need web3 interface which interacts with smart contract and each of investors every month have to collect tokens manually or can it be airdropped?