I almost got the 5" Cobras when I saw it in the mini set with the 6" Pliers Wrench. But since I couldn't actually see myself wearing the belt pouch I just bought 6" Pliers Wrench and 6" Cobras separately. Both are small enough to still fit in a pocket. And the the 6" Cobras give me 20% more power/range over the 5" size (same math applies to Pliers Wrench).
If I need a really small adjustable wrench I use my ChannelLock 804 which is the 4" size (actually 4-1/2" tip-to-tip). They are made by Irega in Spain, re-branded for ChannelLock, and are quite nice, though pricey, for a 4" adjustable. At the plant I work at there was a square head bolt in a tight spot I couldn't get my 6" Pliers Wrench on. So I put my ChannelLock 4" adjustable on it, and used the 6" Pliers Wrench as a cheater so they were both pretty handy.