Linear of adjustment with throttle quadrant or TPM

I use both a Saitek Throttle Quadrant and TPM with various aircraft.  Although not an issue with GA aircraft I find that neither device provides for 'micro' adjustments of airspeed.  

The best way I can describe it is that the throttle movements are not equally linear.  It seems impossible to fine turn a speed adjustment.  As such I experience wild swings of too much or too little.  

I experienced this with the FeelThere ERJ and now again with the Majestic Q400.  It likely occurs with other aircraft, but these two seem the most extreme.

I've got FSUIPC4 and have the spikes setting checked, but any other thoughts on how to deal with this?

Thanks

Ernie