I do CAD so i found a text font. In my case FUTURA BOLD was a really good match, imported it to the CAD program and a photo of the top of the VR.
knowing the dimensions of the VR I scaled the photo to match.
Then aligned the text to the photo.
After, I exported a file ( don't recall the file type, might have been a .jpg, with black solid letters)
I uploaded it to the online company and a week later I had the stamp.