Ok, spent a fair bit of time on this all last night, using the online compression tool seemed to give us a near flawless connection on Sega Rally with Framesync=1 turned on, but we had changed a few settings in the dev file as well, that seemed to help. The cars were stable and no lag on the slaves in Sega Rally. In my case, the time clock has always counted down fine in version 1.0 or higher, was very random in 0.8 and 0.9, not that it matters, you get so much time you couldn't possibly care ( unless it glitches and shows 5 seconds when youre miles from a checkpoint and doesn't change back!! )
Daytona however we had minor issues, as always you can just play it that way and its not a playability issue, with Framesync=1 it was flawless for the first race only, then the other player car was slightly jolting back and forward. We did experience the 2 second pause a few times, but once we got things working well, it was about 6 to 10 times over about 50-80 races between both games.
Im interested to know what else can be changed to make the connection stability better, and in particular what was added between last car and master to fix the 2 second pause issue?
We did try going direct using just the emulator network file, however that didn't make it any better, and in the case of Sega Rally seemed to be a bit worse, which affects the slave cars to what I consider unplayable.
We were using a 24 port NETGEAR managed Gigabit switch, the shortest CAT5e cables that would reach, and onboard NICs, with their settings adjusted for the best performance ( that last item made a big difference ) The NETGEAR switch did make a difference over my 8 port DLink non managed Gigabit switch, however that NETGEAR is not exactly cheap either.