I have successfully imported ad groups from Google into my Yahoo account, but I'm tempted to just completely optimize my Google account (I just started with my company and I'm taking over mgt of their paid search) and import the entire Google account into Yahoo and overwrite everything. My main concern is the potential spend level differences. I know you can set daily budgets, etc., but I'd rather not limit the account if I don't have to. I'm interested to hear if anyone else has done this and seen a jump/drop in daily ad spend in your Yahoo paid search accounts.
My first warning - be very careful with your content match keywords. every time i imported my google campaign, the account reps bungled it and matched the content bids to the search bids...imagine paying 3.50 a click on the content network! they refunded me. both times.
As for your question, i wouldn't worry about it. true, there are differences between industries, but our Yahoo SM traffic is about 15% of what we get from google. I wouldn't worry about limiting the spend...as long as you watch out for the content matching!
We tried the exact same thing. We took the better performing half of our AdWords account, and converted it to Yahoo. The result: 80% of both ads and keyword declined for editorial reasons. These were proven keywords, ads, and landing pages with great ROI and the content is nowhere near anything questionable. It seems that Yahoo needs a lot more hand holding to get up and running. We had to rewrite everything and even redirect some terms to new landing pages to finally get everything approved.
You may have much better luck, keep us posted on how it goes.