I guess it depends on what you want. If you want "max" out of it, drive it around 1.8 to 2.2 (?) amps as many of the hard driven Q5 throwers are already (my Dongrui All-920 pulls about 1.96A, the UltraOK Q5 thrower pulls 1.60A, and there are reports of A60's pulling upwards of 2.1 amps. So maybe you aim for 1750 (AMCx5).
-Garry