The maximum file size on an NTFS formatted Windows 10 PC is at least 16TB. I only have 1 to spare on my current internal HD, so I don't think file size will be a problem
I need to plug my capture device back in and fire up the software as it gives you a very simple and clear "n hours of recording space available".
And it has crossed my mind that I may end up on a screen saying I've lost connection and to hit X to join online, so I'm going to check in once a day to make sure that's not happening, but not do anything else. I'll either take my PS Vita or make sure my phone is able to connect before I go.
Wait, ah, smart, so you will be recording with external software and not R* editor, yeah recordings will be limited but at least you will have recordings,
there is one more idea if you're willing to do it, since the recording through the R* editor is limited by the game to 50GB max ( I think) you can just move those files from that documents>GTAV>Clips folder and store them somewhere else and you will have more 50GB to record, i also think you can just move those .clip files without closing the game. just try to do it before the main days. as you will only have to do it twice or thrice since as i mentioned early a day's recording wont be bigger than 24GB.
Edit: oh so you're on PS4, is there any way to move those R* clips on consoles? if not then the external recording is the only way.