The logfile will be appended with positions. Logging 30 days will most probably fail when trying to upload more than 3000 positions.
We tested and with a good (activesync) internetconnection you can send about 4500 positions at once, before a buffer error occurs.
My advise would be to try it out already today and tomorrow, just keep LOGGING and then upload. We will put the positions at the right date, no worries for that.
For 30 days, my advise would be to cut-paste positions.log to your storage card, per day, and when you get back, copy paste the positions.log in the directory you took it from, and press "send records"
When that is done, the file will be deleted, and then you can copy-paste the next positions.log from your backup on your storage card to the client directory. Repeat this step for each day. You can choose to only make week-files, then you only have to do this 4 times.
You can also just log and log and log and then try. Before doing so, make a backup of positions.log.
A community for and by the people, the ideas are endless, enjoy !