Yes you can get base tints at Sherwin Williams. However, getting the code these days are harder to find for the old fashioned machines but you can do it if you can find tint codes.
Good luck, get ready to have some spare messed up gallons. lol

Thank you
Adam Cavenagh

You can buy single bottles of universal tints for paints and stains at many paint stores. These bottles are used in tint kits for custom on the job tinting. I have a tint kit and it does come in handy.