Well, obviously I'm going to say yes, but apart from the very real need to feed my children, why would you bother making a best man speech to a comparatively small crowd? It doesn't matter how many people are there, the premise of the best man speech never changes: it's your opportunity to stand up and celebrate the groom in a really entertaining, memorable and meaningful way. It is the very act of doing this for him, in front of people that he really cares about that is important, and so you can't put a value on it depending on how many people might be listening. And let's not forget that most of these smaller weddings are being videod to be shared en masse, and some are even being streamed live, so you might think there's only 29 other people in the room, but it could be several times that figure.
What you say, no matter how big the guest list is going to live well after the wedding, for better or for worse, so it's up to you to get it right, and being a smaller, more intimate affair, it's going to dictate what that speech looks like. You really won't have to make the same introduction, it should have a much warmer and friendly feel to it, as you're almost certainly in a situation where most of the guests are intimately familiar with both you and the groom. I don't normally include any mention of the best man's parents, but in these scenarios, that would feel more appropriate.
I never recommend using props of any kind, but best men will always be tempted, however, this really isn't the moment. Getting screens out, and showing videos to just 29 guests is a lapse of judgment you really will regret. You absolutely must connect in a very direct way, and there is a coldness to props and visual aids, that just doesn't work for smaller groups. You need eye contact more than ever - you can get away with less eye contact for big groups, but if you're stood in front of 29 people and just have your head buried in your notes, then it's going to get very awkward very quickly.
