Keying Circuits for sweep tube linears

[Rhinoky]

Hello all, I am trying to help a friend find info on a keying circuit for a sweep tube style linear. I was told the transistor used for a tube style linear was different than that for a transistor style linear when building a keying circuit? For instance, I was told he needed a darlington style transistor where the other linears use something like a 2n3906, 2n2222a or a 2n2905a. Does anyone have any info if this is true, or what actual transistor would be needed for this keying circuit for a sweep tube box?

Thanks in advance,
Gary

 

[VMC]

Here's some circuits from pg. 348 of the 1984 ARRL Handbook.