It’ll give you a toasty, somewhat deeper malt flavor as opposed to the pils alone,ie., a very nice beer. I’m speaking of non-lodo brewing as I haven’t used it in that format.
I’ve only used Vienna in combination with Pilsner and Munich. That beer tasted great and to my surprise won a competition. I got good bready grain and caramel. The caramel likely came from the Munich. Not sure if the bready flavor was from the Pils or Vienna malt. Regardless, sounds like you have a good Vienna Lager planned.