Accessories - Housewares - Finishing Touches - Help hanging pictures

I hope this is the right forum for this question. I want to hang four 16 X 20 photos together. Each has 16" for the height. I plan to hang them in a rectangle on a 9 foot wall (8 foot ceilings). Combined with frames they should equal about 45" wide by 37" high. I plan to center them left to right but am not sure how high to hang them. This is the back wall of the dining area. It will have a round table and four chairs right in front of it. Suggestions please.

Oh I have a second question. Two photos are b/w and two are color. They are scenes from the 1950s. I was thinking I should put the b/w kitty corner from each other. That would mean the color photos are also kitty corner. Does that sound like how you would do it?

I would be happy to give more detail if it would help.

Lay pix out on floor and place your four fingers between the pixs and arrange to achieve a sense of balance. No space greater than four fingers or 4-6" apart.

If to be viewed from a seated area, such as a dining area, hang low, where bottom of 1/3 is at least viewed from seated area. If pix are in an entry or hallway, hang higher where pix will be pretty most centrally at eye level as you walk by at a higher level than when seated in a sitting area.