1200mah/ 6.0V NIMH battery powering Futaba S 3010s on a SIG Four Star 60.
******I've heard you need to cycle batteries to get better performance. I don't have a cycler so I just hooked the battery up at home and periodically checking battery indications on a load bearing checker. I realize this isn't the perfect way to do it but that's all I can do right now.
QUESTION: HOW LOW SHOULD I CYCLE THIS BATTERY DOWN TO BEFORE I BEGIN A TRICKLE CHARGE BACK UP TO FULL CHARGE?

Don't cycle NiMh batteries. Cycling was for NiCd technology. NiMh don't need to be cycled. Periodically measure the capacity of your pack by discharging it on some known load. You can buy a discharge measuring device or you can just measure using your loaded voltmeter. Let's say when the battery is new you can fly 6 flights of 10 minutes each before you loaded voltmeter show 4.6 volts. After 5 or 6 years of use, you note that you can only go 4 flights before the same voltmeter reads 4.6 volts. Your pack has lost some capacity and should be replaced.

I'm using a "CIRRUS" Cycle Pro Battery Manager, and the cycle will discharge to no less than 1.05/cell (a 4.8V=4Cells)
This is the minimum safe voltage for a battery pack, Then fully charge automatically to complete the cycle
I think this Cycle-Pro is one of my best investments.

Precision & Consistency

The only time you need to cycle a NiMh is to check for capacity. Check out www.rcbatteryclinic.com for some good advice on the care of you batteries. To get the most out of either NiMh or NiCad, you need to form charge them. This is a charge at 0.1C for 16 hours. It may take two or three cycles of this to bring them up to max capacity. Discharge between charges at 0.25C down to anywwhere from 0.9 to 1.1 volts per cell, use the 0.9 figure if you are comparing results to factory specs. If you use 1.1 volts/cell you will get a lower mah number than when using 0.9 volts/cell. Note that charging at 0.1C is defined as a slow charge, not trickle charging. It often helps to do a slow charge for 16 hours on both NiCad and NiMh batteries that have been dormant for a time or have had a few fast charges put on them to bring them back up to a higher capacity.

NiCd - Big benefit from cycling

NiMh - very little befit from Cycling

Lipo - No benefit from cycling.