I have used a small bolt and some black silicon for this

The plugs that go around the cam fit.

I have a dipstick tube that I welded a strap to to bolt it in the block right below the dipstick. You could do the same and add some silicone to it before you slide it in..should fix the issue. I was using a chrome dipstick too. I can probably post a picture sometime if needed..

I'm with you an this one I used a wheel weight lead cut it & hammered into the hole noy realising that a cam oil gallery plug fitted, the lead worked a treat too