I saw a video on via this site, they used what I think was sota straws in lou of wood dowles, it that ok how much can it hold

I wouldn't use soda straws on the bottom of a large cake (3 or more tiers) but on a small two tier or if you just want to support a topper I would think that it's just fine. You could use larger straws or use the ones that duff uses on his show (don't know where he gets them though). The bigger the diameter the more weight it will hold.

some discussion:

http://cakecentral.com/cake-decorating-ftopict-270153-bubble.html+tea+straws

http://cakecentral.com/cake-decorating-ftopict-419223-bubble.html+tea+straws

http://cakecentral.com/cake-decorating-ftopict-400323-bubble.html+tea+straws

http://cakecentral.com/cake-decorating-ftopict-72551-bubble.html+tea+straws