My group is not in to loads of dice rolling so I've cut the space combat by dividing all the combat stats by 10. So a Heavy Laser does 8+1d8, Hyperion has 2 DR etc.
As for fighters, they have to act in squadrons and I’ve pinched the chart from B5W to work out how many fighters in a squadron hit their target. Each hit does 1 damage and no DR. This allows them to be a bit more dangerous to the bigger ships (explained by saying that they can target the weak points on the hull e.g. turrets, sensor pods etc).
I’ve not got the fighter to fighter combat sussed yet but I’m working on it!
If you want a really big fleet battle there were a good set of rules for Battlestar Galactica on the web; that was only a couple of dice rolls per capital ship so you could even refight the liberation of Proxima in one evening!