Trust me, you'll be wanting 1 post per 24 hours when we do battle. During the pre-launch mocks Greg and I ran, most battles were decided in 2~3 days... so for battles I wouldn't worry about speed at all. I mean, a STRK can dish out 172 damage + 42 systems to a CORV in one shot. One more shot and it's knocked out. A third shot and it'll blow.
So, a typical battle may start like this:
1. Rebel Fleet Alpha exit hyperspace in Ralltiir's deep space (posted on the HYPERSPACE thread). If the planet has a Level 5 ComScan, then the defending player will post "Level 5 ComScan active, please post unit locations at Ralltiir" (or something to that extent), if not, then proceed to step 2.
2. As soon as RFA moves into high orbit (C-ring), the planet automatically becomes aware of their presence and a General Distress Signal is sent out (x2 hyperspace) via civilian channels (if you have even a Lvl1 ComScan, then a faster distress signal can be sent, but this is not automatic so the player will have to post that one). For a GDS at x2 hyperspeed, the message will take 14 hours to reach Chandrila.
3. RFA can assume to have at least 28 hours of unimpeded combat action (14 hours for the distress call to be received + another 14 for a response fleet to show up). The further away the planet, the more time obviously, but you get the idea. Basically after moving into the C-ring, you'd get at least one post (under this scenario) to do whatever damage you can before the hammer drops.