Thank you for clarifying those points.
So, unless you want to accurately calibrate your emonTx/emonPi accurately against your meter, the optical pulse sensor will not be very helpful.
Only yesterday Chris Wilson Large discrepancy between pulse counter and CT - #3 by qris had exactly the same problem with his electricity meter.
I think you can do the monitoring with an emonPi (with 5 V DC power pack and cable, a.c. adapter and 2 c.t’s) - the Solar PV Bundle, and I think you can divert the surplus energy either with an emonTx to which you add a power switch (a triac), or you can buy Robin Emley’s Mk2 PV Router in kit form to build yourself. You can of course also buy a ready-made diverter, but you then must rely on the manufacturer for support. I recommend Robin Emley’s Mk2 PV Router - he developed it here and we know it well, and there are many units working successfully in many countries.
I do not see a need for a second emonTx, unless it is not possible to run or extend one or both of the c.t. cables. If your PV inverter connects near to your main (grid connection) meter, then there should be no problem. You put the emonPi near the meter and have an Ethernet cable to your LAN (the emonPi comes with Wi-Fi, you can use either Wi-Fi or Ethernet).