Thad, I guess you know you just opened a can of worms!
How long a blade do you intend to make? The ones you show are pretty small and the type of forge you are talking about will work. Every forge has it's pros and cons. It might come down to deciding which you are willing to make or use. From there, you'll have to go through a learning curve to use it. Again, each type of forge has it's own good things and not as good things. For smaller knives, you will just need a smaller chamber that can be heated.
You will always have to do the work and not let a blade sit there and expect the forge to heat it evenly. You will have to have tongs or pliers and will have to move the blade through the hotter areas, if that is the case, to achieve even heating. Back and forth to get keep control.