Here is how it works

Do not put gift registry on your invitation. The guests would know that you prefer cash,check or credit card.
I have one guest show up with nothing but I do not think he didn't understand the rule.  All other guests give cash or check.
If you attend wedding as a couple you should give $200. If you go solo $100. My hu*****and's side of friends are actually more generous than my side. So I would not say Caucasians are not generous. But we also have a lot of mutual friends.

Do not assume it is cheap in Chinese restaurant. Mine is not in Chinese restaurant because my hu*****and thinks it is not appropriate consider majority of my guests are not chinese. One of my Vietnamese friends have their wedding at a Chinese restaurant. The food is great. It has shark fin soup and other goodies. I didn't ask them but it could easily cost $100/person. I think the reason they go with Chinese restaurant is that most Chinese restaurants allow the couple bring their own alcohol. Western restaurants would not allow that.