This is actually very simple to use, bit slow though so I would recommend writing .bat for all of your videos and then let your PC run 24/7 to DL all, especially if your collection is that big..
But anyway.. Not sure if you guys read the readmes and FAQ's so here is very short and quick guide to it.
1. Use Chrome and install extension called "Get cookies.txt"
2. Login to R18 and go to your library. Use that "Get cookies.txt"-extension. Save that .txt as cookies.txt in same folder with JAV-IT.
3. Get the ID of your video, you can get the ID if you either watch the video or go to the videos information page if it hasn't gotten removed from sales yet. The ID is in form of something like pppd00666, sometimes it might start with h_
4. Go to folder with cookies.txt and JAV-IT. Create a folder where you want to save your video(s).
5. Open command prompt in that folder
6. Type "jav-it download /c cookies.txt /i <THIS IS WHERE ID GOES> /o <FOLDER FOR VIDEO>" obviously without the " and replacing the <> with appropriate texts.
7. Wait for it to finish, this took me about 35-40 minutes for 1 hour video so you can estimate from that how long it will take you.. I would guess several months with that 200+ videos
8. The video is in .ts format so I would recommend converting it to something more appropriate so it will be easier to view on all your devices
And making the .bat of these is as simple as:
Open notepad, write the text of step 6 to it multiple times, and change ID and folder if necessary to the correct ones and save it with any name you want, aslong its extension will be .bat.. It has to be in same folder than jav-it. And then you just double click on that file and let it run.
Not sure about if you can open multiple instances without issues though.. I would imagine R18 servers would prevent it somehow
And you might need to update your cookies file from time to time too for this