I have both 15" BAS 1.25 lbs and 18" WW II 2 lbs.
Jackal, for the sake of discussion the difference between WW II and BAS are in the length (different in 3") and the weight (different in .75 lbs).
I am 5' 6" and 143 lbs so I'm more comfy with BAS. Ferdinand is 5' 11" and 220 lbs so I guess he should be better off with 18" WW II....
mohd:
I agree with most of your posting. However, all HI models come in a variety of lengths and weights. Your particular WWII is longer and heavier than your particular BAS, but some BAS are longer and heavier, while some WWIIs are shorter and lighter. As far as DOTDs on this forum are concerned, in the past several years I've seen many more WWIIs than BAS, so availability might be an issue.
In spite of the variation in lengths and weights, some generalizations can be made. For example, a 20" Ang Khola (or CAK) will likely be too heavy for extended use by most forumites, because the AK is a very heavy model by design and there is usually a huge difference in weight between 18" and 20" for a given model. That's because everything (length, width and thickness) tends to be proportionately bigger. On the other hand, a 20" Chitlangi or Sirupati will probably be significantly lighter weight....
For general purpose usage (camping, hiking, chopping) I suggest the "80-20 rule." In general it says that 80 percent of the cost of a project is due to the toughest 20 percent of the specs. For purposes of choosing a knife, I'd say to buy one that is ideal for the most common (80 percent) of your expected usage, as long as it can handle (perhaps not perfectly) the least common (20 percent) of required tasks.
When someone says "camping, hiking, chopping" I would pretty much rule out anything like a 20" Ang Khola. Even if the user is a big guy, why lug around such a heavy chunk of steel? If it's for the exercise you can pack along a barbell. A 15" CAK or an 18" WWII will probably be similar in weight, and either one can handle all normal camping, hiking and chopping tasks. I agree with you that an 18" WWII would be good for a big guy like Ferdinand. Probably even a 16" or 17" WWII, depending on how much actual hiking is involved.
One other thing: When someone new to HI says that he wants a "big chopper" I would take that with a grain of salt, since even the lighter weight HI blades might be considered "big choppers" compared to other knives in the non-HI world. For example, a 1/4" spine is considered quite thick for most non-HI blades, but in the HI world 3/8" spines are more common and even 1/2" spines are not unusual for models like an 18" Ang Khola. Many people when they get their first HI khukuri are pleasantly surprised at how massive they really are.