Gary:
On my Kirkham, I have springs on actually both ends of the shaft against the two bellcranks. As far as tension, let me suggest that you set the tension just firm enough for the retaining washer to keep the cotter pin from falling out. This is really not much compression as you can see, but you really don't need any. What you want to accomplish is taking side slack out of the cross shaft while giving it a bit of lateral "give" under pressure.
Bud
