Te Velde is obviously a lot more up-to-date than Budge.
As far as that sign goes, my dictionary (Paul Dickson) translates it as cut, separate, discern, judge. Used with the god determinative as a name of Set, he renders it as "he who is judged", but he could just as well have said "he who judges". Te Velde's "he who separates" makes more sense to me, but we really can't get any further without an explanation from an Ancient Egyptian!
On the matter of pronunciation, the three hieroglyphs are consonants, transcribed as "wḏꜥ" (or wDa on fontally-challenged computers!) The convention in Budge's day was to pronounce them as "ucha", while today it's generally "weja". Needless to say, the ch/j in the middle wasn't ch or j! In Classical Egyptian you could turn the verb "separate" into a noun "separator" by changing the vowels, but we don't know how it was done. In the Roman period, you'd probably say nuti-wôč, literally "separating god" — I know they said ref-wôč "separating man" for "separator".
