Help with prong setting design for radiant cut diamond

[ianb.3]

Hello again, new to this forum just introduced myself, I am currently in the process of designing an engagement ring for a .9 carat radiant diamond. I'll prefix this by saying I have almost no clue what I'm doing but I am going to go ahead and do it anyway, because I can. I am designing a ring based off a ring my girlfriend made for herself a few years ago, just looking to add the stone on top now. I intend to have it printed and cast by shape ways and then Ill finish it as close as I can before working with a local stone setter to have it completed. I am struggling to design the correct shape of Claws for the setting, and can't seem to find enough info by googling. If somebody can take a look at the photo and tell me if I am going in the right direction or not that would be great. the stone in the picture is the exact dimensions as the one I am getting, so just need tot design the prongs around it. Ideally I would like the prongs to be rectangular shaped and come up out of the side of the ring with the long edge in line with the edge of the ring, then twist 45 degrees (approx.) to be in line with the edge of the stone. I am working in sketch up and drawing the fluid twist is a little beyond me so right now contemplating casting them as is and just reshaping them by hand once I have the ring.
Main questions
what thickness is needed for the prongs to hold a .9 carat stone? currently i think they are about 1.3mm x a tad less than that
are the prongs rising up at the correct angle?
should the prongs turn up above the stone to minimise work after casting?
am i a complete idiot?

Just to clarify I am aware the internal shape is not typical but I assure you it fits just fine.

Thanks in advance