It would depend on the amount of oil you are using. If you are taking a tiny micro dose, like under 1/2 cc a day, that works. For your delts, a 1/2 in would be ok, most of the time but really you can do a 1 in in your delt, no problem. Main thing I’d worry about is putting a bolus of oil that close to the surface. You are a lot more likely to get muscle irritation and possibly an infection. I would go with a traditional injection using a 3cc barrel. For quads, 1 in. For Delts, 5/8 in. based off the gear you plan to use, I can see you are going to need to inject too much oil to do this safely