This is a good question yet it's quite hard to answer for me so I just want to forward it out again by responding essentially. I've deleted any backups of profiles that I have installed and yet it takes up 18 gigabytes of storage on my pc which is crazy. Not sure if it's because all those mods take up that much storage or not, but I guess this might help answer your question it takes up way more storage for me than I thought it would. I guess it also varies depending on how large the packs are and how many profiles you'll have installed. I have 3 packs with 100-200 mods and one with about 12 and it takes up that much storage (18 gigs).
So to answer your question just give it a shot and if you need space be conservative and only download what you need. I'd like to ask a question though, where else is data stored other than these 4 profile folders? I feel like Curse should NOT take up this much storage so what should I do instead of having to delete and re-install the whole entire application exactly? Does anyone have another place to look to clear up space? Or is it simply the case that these packs take up that much space.