If Revolut asks for an account number and an ACH routing number, this means that Revolut is going to execute your transfer as a domestic ACH transfer.
I don’t see a compelling reason why anybody would want to use SWIFT if a domestic transfer can be used. (Ok, there is one possible reason: If the domestic transfer is being made by relaying funds through a pooled account, SWIFT could have the advantage that the beneficiary could see the correct origin account on their statement. But I don’t think that this is going to matter when you’re sending to yourself, especially if the account is with TransferWise which conceals this information anyway.)
Can you elaborate why exactly you want to make a SWIFT transfer to TransferWise?