Changing the paging file size, in my opinion, is only used as a last resort kind of thing and/or if you are in desperate need of more virtual memory on your computer. The drawback of adding additional virtual memory is once your computer has used all of the available "virtual space" you add, your computer will become even more bogged down or slow because there is no more space or a place for files and data to go, and it may even result in adverse effects/issues in the future.
Again, this is my personal understanding of how increasing paging file sizes can have pretty serious consequences if it hasn't been setup correctly and misused. But if this method works for you, then all I will suggest is just monitor your hardware for a while and see how you get on. If issues start to come up just revert the settings back to default and let your computer work things out automatically, which is usually the better option.
Unfortunately I can't say for certain why Lighthouse is the way it is. I can't seem to have any successful raids on that map as my character bugs out, resulting in ALT + F4'ing and restarting the game. Hopefully it'll get fixed in the future.