I have (mulicollatral)Dai v2 in the wallet and I want to set the minimum possible gas limit such that my send transaction don't fail. Thanks
It doesn't matter if you put more than required, because you'll always get it back
There is no single answer to your question, because the required amount of gas may change from one transaction to another, depending on the state of the blockchain (i.e., the value of every state variable involved in the transaction)
It also depends to a certain extent on the compiler that you're using, because different compilers may generate different bytecodes
Note that you still want to use the minimum amount of gas required, because miners choose highest-price/lowest-limit first, so your transaction will likely execute faster if you choose a smaller limit. For that, you can simply call
estimateGas before sending the transaction, which will give you the exact amount of gas required in most cases.