I'm not quite fond of your routing either, but understand you don't want to change it, so I have a couple simple things you might try...
- The hoses on either side of the Flow Control Valve: switch them so the valve is closer to the chamber for more accurate water delivery.
- A Y would be better to combine the cylinders, but try having the two cylinder lines coming in from the top of the T and the pisser coming from the bottom; should even out flow and temperature between the two cylinders. Right now, your front cylinder flows straight through the T and the rear cylinder has to merge in with a 90 degree bend...
Just remember, if you wanted "good enough", you'd still be riding a super jet with a 650 or 701. You spent all this money, you should want the most out of it that you can get!