Well, having run irons in competition, post front only, for yeras, what I can offer, I would do nothing on the front other than a square post.(rectangle) Any other shape does not give you crisp enough reference to the front, especially the fire type optics.
The front is the most important and has to be as clear as possible.
Secondary to that is clarity of target and it can be pretty fuzzy.
Rear sight distance can be very iffy to my eyes on a groove. But a peep is not nearly as picky IF you can control the size of the aperture.
IF I had to go with what you are using for a rear, I'd put the front on first then tape or glue the rear in a few differnet places and just go outside and see what my eyes, with correction that you would be using, tell me is best.
