Ok, let me see if I can get this attached. No doubt it'll probably either small or a grainy picture.
First of all, keep in mind this is an old house, probably 1900's give or take a decade. The front of the house is built on stone foundation and the rear is on CMU but over a crawl space. Both the front and rear of the house framing sit on large wood beams, about 10" square.
The circled yellow, the longer one is the beam that runs the back wall of the front of the house.
The shorter perpendicular yellow is beam running along the side of the back of the house over the crawl space. Where these beams meet was two other beams, one somebody hacked out and the other, I made a beam hanger and attached it to a beam in the ceiling.
The red circle shows a header/joist from the original location of the stairway. At some point it was moved and smaller 2x6s were added to fill in the gap.
The blue on the right is a floor built on top of another floor. The lower floor looked to be an old porch floor. Notice the old sewer stack that I had to remove.
The green on the left is a floor that was fairly solid, as compared to the rest of the floor. However, it ran between some large beam.
The gray in the upper left is my closet. I already had this section done, glued and screwed, it wasn't coming back up. It was a floor on top of another floor raised up at some point.
All in all, there was literally 4 different floor levels, all built different. Sistering some joists would have be nice, but they weren't there. I did the best I could with what I had. When you remodel an old home, sometimes you have to get creative, very creative. The floor is solid now, very solid. It's glued, screwed and nailed. I used PL375, I think, and I was very liberally with it. Honestly, I pity the poor fool that ever tried to remove it.