regarding the second question, Imho, go 1243 or 1144.
Don't worry too much about da... At level100+ knives easily have 40+ da. And you'll have a nice base to work with. The real important matter is dp and md. Some lk and Hv are also important. Don't go pure da. Imo, its a waste of points. Go dp/md or pure weight. Purr weight allows you to afk for a while, and it has some really good utility. Dp and md build.allow you to potentially pump your Equips with Hv lk and HP which are really important.
As a reference, my 1144 fox can afk at ghost blue with about 1.2k dp, and 1k md. (provided by a single ult.crest shield) the hat is used for a bit of dp and da, the knife if da, and accessories are HP and Hv compounded. She usually doesn't die.