Some thoughts from a fellow author of a Catholic novel (THE GENTLE TRADITIONALIST - see my signature below for details).
I think 474 is excellent for the circumstances you described. My own book has sold maybe 2000 in the last 9 months - BUT I got published by Angelico Press and their publicity skills are remarkable.
Without them, I am sure I would be struggling for 400+! Self-publishing seems a very tough way to go if you want significant sales in a world hostile to Catholicism.
Although I owe most of my success to Angelico Press, I do have two or three tips.
Most importantly, there is an absolutely excellent resource book called PLUG YOUR BOOK by Steve Weber. You can find it on Amazon - worth every penny …
Second, I think having an extensive website has helped me, along with active engagement on Pinterest.
The size of my site plus my regularly pinning graphics from my site means I get a decent amount of traffic from both Google search and Pinterest.
I also have the first chapter of my book online (here
corjesusacratissimum.org/2015/11/the-gentle-traditionalist-chapter-one/)
And in addition to using pins, I have also used Facebook groups to promote that first chapter. I do find that people surf to that chapter, get hooked and buy the book.
Again, Steve Weber has
many more good ideas. Do check him out, if you haven’t already.