Making light colored decals for use on dark backgrounds

Has anyone had any experience with making decals of small, light colored numbers or letters to go on dark backgrounds? I found ink Canon jet prints are far too transparent on testor’s clear decal sheet, so the light colored letters don’t show.

Has anyone ever tried the “T-shirt” transfer option on Canon’s bubble jet printers, does that produce a thicker, more opaque layer of paint?

I haven’t tried the t-shirt transfer method, but have tried just about everything else. The only thing I have found to work is using white decal paper and fill the surrounding area with the color that you are putting the decal onto. I did this on my 160th SOAR MH-60L DAP Blackhawk. All the OD decals were made in this manner with a flat black surround to be placed on a flat black model.

Here are the results: