Unless the video IS by someone notable, I would put much more "salt" in Mr. Vizard's book. Misconception is among the most common areas of ruining heads when trying to "port". A "litttle" IS better unless you're shooting for super-high revs and don't care about low-end.
Also be careful comparing heads using runner volumes. Not all ports are "equal", even when they're the same "size". Extensive use of "inside" and "outside" calipers (dividers) is necessary. Cross-section MUST be maintained up to the "venturi". Use a smaller OD valve as a "gage" for the bowl/throat work.
Although the video is not using Chevy heads, Pete McCarthy has an excellent video porting Pontiac heads. The majority of the fundementals are the same. THAT video might offer some insight giving you an advantage. For those not familiar with Pete and his work, he's one of the guys responsible for the "Angeles-McCarthy" '68 Firebird C/SSA that has been a class and race winner at NHRA events over the last 15 years, sporting a 400 Pontiac and running in the low 9s with a Q-Jet. He knows what he's doing... Pete's getting on" these days, but his books and videos are stilling selling well.