One nice thing about PbP is the slower pace helps with all the little stuff, like the +1 here and -2 to hit there. At least I find it easier, but from the DM side it's gotta be difficult.
In L4W, I'm getting nervous to run Paragon games (which we seem to be getting closer to), but also a bit excited. Epic is crazy though.
I think splitting up the initiatives is a good idea. If there's 6 of us (assuming we all survive) not sure if its easier to do 2 groups of 3 or 3 groups of 2. The latter will be more updates, but of smaller size, the former less updates, but a bit larger. Depends on the # of enemies I guess. If there's a lot of them, breaking them up more is probably better for you also.