RE: 8 v. 6. Hi-Lo shows 8 double at 1+, but it says split 4's (das) at -5+. Thus, I assume that splits are more robust with DAS than DD, and one should always split 4s in lieu of doubling. Correct?

RE: 16 v. A. Hi-Lo sez Surr. 16 within the range of -4 and 16. I assume you hit below -4, but stand at +16. Correct?