I am running the 170cdi in both my Valiants. LR85 Hyde mount. All servos are JR digitals. 9411 on ailerons, 8511 on rudder, 8231 on elevator (pull/pull) and 362 on throttle. Battery is Duralite Li-Ion 4 cell 4300 (redundancy) pack. This is the same weight as 2 x 1100 Nicads. The ignition draws from the Rx pack through the Aero Tech IBEC.
I can get alot of flights with this set up. The battery loses approximately .07 volts per 8-9 minute flight. I have never had to charge at the field. The only downside is about an extra 100grams for the 4 cell pack, but i can live with that as i have the redundancy in the event of a cell failure. Which hasn't happened yet.