Can you set a 3 carat oval with 4 prongs instead of 6 and feel safe?
If I don''t want the 6 prongs, since it comes off looking like a marquis, do I need to go with the double 4 prongs or would 4 plain old prongs work fine?
There seem to be a few ways to place those prongs... is the one you want to avoid anything like the drawings below?
The main objection against four prongs, is that it takes one bent prong out of four to loose the stone, while five out of six still hold it. This is true, but not a daily hazard. I see no reason not to get exactly the ring you want, insurance and all
On ovals I like to use 8 prongs, actually 4 prongs with either split tips or 8 individual wires, but closely paired so you have double prongs holding the stone as the lower right 4 prong image above, instead of only 4 prongs. This allows effectively wider prongs without added thickness away from the diamond. It is more secure and good looking.