Now you know what you can show and why you should get a mosaic floor in progress for your villa before you go any further you need to establish one thing; tesserae, how you are going to get enough for the project. Do not do anything else as this is the one thing that will determine if you can make this a reality.
There are quite a few options and I will go through as many as I can think of. First what sort of tesserae do you need? I am not going over using modern materials, this will be easy enough for you to work out by going to mosaic suppliers for this. This is solely about getting marble/stone tesserae.
The average size of tesserae in a Roman mosaic was 10mm (3/8”) square. They were, obviously, hand cut so they were slightly irregular and the edges might be anywhere between 8mm - 12mm but they still conformed to this average size. With the material we have now it is all cut by machine so the tesserae are exact squares. Whilst not impossible to use these can give the mosaic a very flat, and what I term, ‘industrial’ look. The best option then is to get something that can be finished in the way you want.
For nearly all of the following you will need a hammer and hardie (H&H) set to cut. Any marble over 6 - 7 mm will need ot be cut with these to avoid over stressing your wrist. Unless otherwise stated we are talking of marble that is 10 mm thick.