Bridging Gaps

It's been a while long time since my last post. The Great Laziness set in on me for the winter, then I had to go to LA for a couple months for work. Extended trips tend to leave me in another state of laziness when I get home.
Now, I'm back to being productive in my East room wing. I spent my Sunday installing bridging between floor joists in an attempt to stiffen things. First, I tried the metal single-nail tension bridges. It worked between a couple joists, but most gaps between joists were too wide. I ended up putting a 2x8 bridge between most of them. It helped some, but, like I expected, there's still a fair amount of bounce. Securing the sub-floor and finished floor may help some with that, but most likely I'll install a beam underneath to keep things from bouncing.
If you're wondering about the black strips on the joists, that's roofing felt. It's often used on top of sub floors to get rid of waviness or general unevenness. I decided that since I had a few joists that were 1/8" or 1/4" too low, they could be a good solution to even things out before installing the subfloor.
One thing I need to figure out is how to fasten the subfloors with strips of roofing felt below them. The normal method is to put down construction adhesive and nail the floors down. I've planned on using screws to hold the subfloor down. At this point, I can't decide if that's enough since construction adhesive on the top layer of roofing felt wouldn't do anything. Maybe I'll just break down and glue every layer of felt beforehand just to be safe. After all, it's only 4-8 layers on 5 joists for 13 feet.
Actually, that doesn't sound too bad.
In the meantime, I need to research thermal breaks between the wall and floor's edge and also research putting up new framing for the walls. I've decided that I should frame in new walls 6" from the exterior walls and put in insulation. In other words, I may have this room finished in less than a year and a half, but it might be closer to two.