At least in my experience, you'll be ok with a normal stopper/blow off valve. Only time I've ever had to use a blow off tube was for two days after I added apricot purée to my secondary for an apricot wheat. Lots of sugars, obviously.
Unless you're putting something in the secondary that's going to have high amounts of fermentables, I imagine you're ok with the normal stopper. If you're pouring coconut flakes, for example, just make sure to sanitize before pitching and throw the desired amount in. I'd say soaking the coconut in vodka for a day prior would be good - just pour all it (vodka and coconut) in.