So you'll be:
- manually recording approximately one thousand tracks
- probably wanting to top-and-tail most [if not all] to remove overly long silences
- possibly normalising these tracks [depending upon how you record them in the first place]
That's a lot of time and effort to end up with a lossy format.
Go FLAC. The savings in file space you'll get over WAV will really add up over 1000 recordings, and you'll have as perfect a backup of your vinyl as you can hope to expect [depending upon your recording methods, of course].
You can always batch downcode to mp3, ogg or some other lossy format from these FLAC 'masters' at a later date.
[EDIT: Best size/quality compromise? If you're adamant about mp3s, then the best bet would be variable bit rate [VBR] files that are roughly equivalent to 256k-320k constant bit rate. Again, not something I'd do, though]