Darlington Build Question...

[petemoore]

What is the criterion for transistors used to build a Darlington ?
 Do they have to have a certain amount of gain to work?
 I can't find any 5089's, NTE guy down the street must special order any high gain low noise and Darlingtons...
 So that leaves 5088's and 3904's, BC108's and BC109C's...any of these suitable candidates?
 Will a  Darlingtransistor for a Tycho Octave's Q1 work?