Okay you suggest leave at unlimited/max if you plan on doing several transactions in a short amount of time then revoke to save on revoke gas fees?
Yes, but only if you know what you're doing and use a reliable service, like Uniswap for example
Do you manually set the approval amount after completing the transaction or before the transaction and if before how you manually set it in metamask and what limit in $dollars should I set it to, for example if its $100 usdt on tron uniswap into $100 usdc on arbitrum then do I just approval to simply $100 or do I have to set it higher to cover network overheads and gas fees?
You have to approve the limit before the transaction
You can approve the limit you will use at the time, most services already set the correct limit, so if you're going to use 100 dollars, just approve the 100 dollars
Take a look here
You just need to set the limit you want where's Unlimited
In Revoke.Cash site utility I see on its Signatures page Tokens with Permit Support and I can cancel potential signatures for each token. What does this mean and if I cancel what will happen to my tokens in my wallet? Signatures require no gas fees right so if I cancel signature there should be no gas fees for cancelling right?
To revoke these signatures, you will have to spend gas fees
Nothing will happen to the tokens in your wallet, they will remain there