I gave CLAT this year and secured a rank of 47X. I thought with my rank I would get GNLU in the lists but after I looked at last year's lists I realised that from the first list to the fifth list there was only an increase of 43 ranks in general category. This year the closing rank in the first list was 429 and by fifth list it could reach maybe low 470s. I think I might miss it by 2 or 3 ranks in the lists so I wanted to know how the vacancy system works, by how many ranks will the cut off increase in vacancies? Will I be able to get in if I missed the fifth list by a few ranks? Please let me know.

There is no certain way to establish whether or not you'll actually get in. It depends on multiple individuals and factors beyond your ability to actually calculate. I'll suggest waiting it out, Gnlu seats will open up and stretch a bit in the vacancy rounds. Infact even NLUJ went for the lower 400's last year so you might get in via vacancy