I ran my 026 Stihl with a 24 inch bar for several years of firewood cutting. I ran full skip chain and it could pull it fine. I have always felt the longer bars were safer (for me at least). Some of my cutting was in Western Red Cedar which is quite soft and generally very easy to cut.
Now I have an 18 inch bar with .325 pitch chain on it. I bought the bar and chain as a combo from Baileys for about $18 or $19. It has been working very well and I am most pleased with the 18" bar with .325 chain.
Jon