If a "full tang is what you MUST have then you can look for pins, which is the best way to know though isn't 100%. Another way to do this is to simply decide which khukuri you want, which type/shape or whatever is best suited to your needs and email Yangdu and ask for one to made in a "chiruwa" version. Then simply wait a month or two and when it is made to order for you, pay for it and there you go!
All of the khukuris made by HI have a far more substantial tang, even the "rat tail" versions, that I don't think you could break them unless you set out to do so on purpose. They simply have far more tang on them than you think is there. It isn't some scrawny little piece of metal that is less than a third of the width of the blade or more like a threaded "screw diameter" thing sticking through the handle. It is then is slathered in
laha, the native glue that is like a rock, and then the handle is put on and shaped. As for the balance question, this is actually something that a good Kami can equal out even without a full tang. I have a hidden tang made by Tirtha that apparently he weighted by using a larger end cap and thereby evening out the weight...
In any case, get what you want for sure but I know from first hand experience and from owning some pretty old and well used khukuries of the non chiruwa type that personally it no longer matters either way. If it is a style I like, then I buy it and never worry if it is a fully or hidden tang, ever.
as an example, here is a picture of the tang of a regular, non-chiruwa AK