Best to try 'em out if you can. Other guys know more about this than me, but I think the biggest thing to remember for amped playing is that you need to create and maintain a good cup on your mic. Try to create a tight air chamber with your hands so that ALL of your harp sound goes right into that mic. You want to form a kind of resonance chamber with your hands. That'll give you the fattest tone.
Most guys rely more on throat vibrato when playing amped.
Let us know how things develop. When you speak of Walter Horton, the first thing you think of is his tone, that big, fat tone.