first of all you I am jealous. I have been wanting a ambrosia for quite some time.
Bulbos like to stay wet and warm (most of them at least) so a little sphag around the roots would eb a good thing if you dont have too humid of an environment.
Without a picture I cant really address the spotted leaf problem. Because they like to be grown pretty moist sometimes they will have some spotting on the leaves that is nothing to worry about, on the other hand and for the same reasons it cna be something that needs to be addressed. Is there any way you can post a picture? I have seen some of that color on some plants before and it was an algae, it could be scraped off with a finger nail. It didnt seem to bug the plant so the owner left it.
Grats on the new plant. hope you enjoy it!