Nice try bro.
You can also try using Male to Male Reverse Lens Coupler.
Setup : Cam + Base lens (Kit lens) + MF Prime lens (50mm f1.4,f.17, f1.8)
With this you can control the DOF better.
I'm using Kit lens 18-70mm @ 70mm (@infinity focus) + MF 50mm F1.4.
With my setup, there's no vignetting so far..maybe if f1.7/1.8 but I guess abit only.
That a bit of cropping may also help you to recompose the frame
A sample below which I intentionally create a 'severe' vignetting..haha..becomes like a telescope.