The only thing you need to do is set the maximum-block-size, max-std-tx-size and max-std-op-return-size large enough in the blockchain parameters, and it sounds like you're already aware of this.
Apart from that you should be aware of the maxshowndata runtime parameter which affects how much data is given in the responses for APIs such as liststreamitems. But this is something you can always change later on, even while MultiChain is running using the setruntimeparam command.
