As osu1991 has already said, VideoReDo is great for editing the files. It is well worth the money. They do have a free trial period for you can see how you like it.
The worst I've seen size wise is 103W Ku NBC feeds which creates as many as 10/11 of those 1GB TS files per ONE HOUR of recording?? NBC on 105W isn't quite as bad but that one does come up to around 8GB per hour. And don't even think about trying to combine those until you make them MUCH smaller, especially if you're using a FAT32 drive.
No i am running ntfs on everything for years now. Fat32 doesn't even support large files sizes does it? Anyway the feeds off 103W Ku are those considered 4K?
whether it makes any difference in file size,I have no idea.