[Elecraft] K2 and TenTec Titan and Logikey -- interface question

[K. Rice]

I want to use my old TenTec Titan amp with K2 #4314 for nets where
I am often having to get a relay working at QRP levels.

Is there any reason not to use an outboard keyer (older Idiom K-3) 
to key the Titan via its KEY IN jack and then use the TenTec's KEY OUT
jack to key the K2 via the K2's key jack with InP = HAnd?

Likewise how about SSB with an outboard PTT switch keying the 
amp which subsequently keys the K2's PTT/dot line by the same method?

As always, thanks to this amazingly competent netgroup. 

73
Ken Rice
K3VV
Coopersburg, PA