Overthinking this ....
If you start with square stock any straight flute 1/4" bit that's sharp will work OK. You can hand rout them with a plunge router because of the "stopped" end. Doing it on the router table requires additional skill because of the plunge and it can get "squirrley" as mentioned. The 3/4" depth isn't an issue with several passes at 1/4" deep.
Practice your method on a scrap first so see how it feels IF you've never done a plunge cut that's stopped. Other than that, it's really pretty straight forward.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
Last edited by woodnthings; 01-02-2019 at 02:50 PM.