G'day Rivets,
From the flight deck you can see the wings and the engines and you could see the effect of nacelle anti/de-ice almost the instant it was turned on.
In over 25 years of flying swept wing jets I've never had the need arise for the use of wing anti/de-icing so I can't help you there.
If you had to conduct a pre-flight wing inspection the best place was from the mid cabin.
Regards,
BH.