Embroidery Question

Some of you will remember the hood project that I began several months ago. I have completed one roundel (of 8). I have the second roundel outlined on the hood itself.
I have finally gotten back to this project. I am finding the large frame that it is on to be very unweildly. I can work with it, as I have a very nice stand. However it is very cumbersome to move the stand in place and out of place when I want to get up. I also recently entered my 7th C Persian sleeves in the Kingdom A&S Competition. One of the comments I received recommended embroidering onto a separate piece of fabric and applying that fabric to the end product to help in placement of the embroidery. I know there is a lot of debate as to whether or not this was a medieval practice or is embroidery was taken off aging garments and then placed on new garments. I think either practice is reasonable. I am concerned about the placement of the roundels if I embroidery directly onto the hood now. As I will be spending literally hundreds of hours on this project, I think I would be absolutely heartbroken if the roundels did not look right on the final project. Then again I'm worried about how applying them as well. I worry how applied roundels might effect the way the hood lies and getting the edges finished well and sewing them on without showing the other fabric.

So I'm looking for advice and other's experience. What have you done in the past, for any kind of garment, what would you recommend?

Thanks for "listening",
Jahanara