130 seems to be the popular choice. Is it strictly necessary, not really. But it will help the engine run a bit cooler, and the top end will pull a bit stronger. I've run 128,130, 132, and 135 on TWs in various setups. Stock with a slip-on I'd probably go 130.
Keihin jets are interchangeable/use the same numbering scale as Teikei jets. They're just a lot more common/accessible/cheaper. Mikuni and Dynojet numbers do NOT compare(different scales).