Normally I only smurf when I jungle.
I will start bot side and clear to 3 and decide on ganking mid or top depending on the matchups. For example, if it's irelia vs darius and I'm playing lee, I'll go top because I wont be able to gank the lane safely post 6 as well as we have cc.
Even if you only burn a flash, it will help the top lane survive the lane phase well you can focus attention on mid and bot.
If there's no cc and they have a mobile champ top, might as well not gank unless there's a really good time for it, such as them diving tower or attacking tower with no ward.
That's really the only time I gank top is right at level 3 or to counter gank.
Bot side is more important for dragon control.
Also top lane meta isn't hard carries. They will scale off, so better off getting mid fed imho, especially if it scales well.
Tl;dr, If he asks for no ganks, no reason to waste your time. Get fed off somewhere else or put yourself more ahead by farming more.