I have a ringmaster built by Tom Morris.  It is as follows:
Motor,   Cobra 2221/10 KV 1500
Battery,  Hyperion 3S 1600 70C
ESC<  Trunigy Plush 30 amp
Timer, KR.  Initial RPMs set to 9500
Weight ready to launch is 27.5 oz.
My thread about this airplane is at:
https://stunthanger.com/smf/gettin-all-amp'ed-up!/e-ringmaster-as-built-by-tom's-building-service/msg563769/#msg563769
It has the battery buried in the wing.  If you move the battery forward you could save the weight I had to add to the noise.

My electric Ringmaster ended up closer to 29 oz and flies OK. 3300 mAh would likely give you about 6 minutes flight time. The OTS pattern only takes about 4 minutes or so. You could save some weight with a smaller battery.

PS - For a more accurate comparison, you still have to add the weight of some fuel to that 26oz glow powered Ringmaster.

What motor and prop are you planning on using?

Delay time from the moment when you hit the button until the motor starts is not included in total flight time.

A 3s/3300mah is way oversized for a Ringmaster.
You could probably safely use a 3s/2200mah and save 3.5oz.
Using Dean Pappas' formula, factored for 11.1v, 30oz and 60ft lines you probably would only consume around 1600mah for a full pattern, even less for the old time pattern.  At 1600mah of consumption, a 2200/3s would give you enough leftover to keep the battery healthy.

With a 9x6e, I would start around 9500 and see what that feels like.  10x6e also works very well.  Start with your existing 3s2200 pack and see what is left in the tank after a 5min pattern flight. 

So i tested the system i have on a mackey profile with the 2200 3s battery and 9/6 prop.  9700 rpm.  Not enough power with that prop.  Will try 10 inch prop next.  Ruined the battery because it ran down to 10% with a 5  minute flightime will try a 3000mah pack next.  2200 would probably be long enough for ots pattern. Flying at  5700 feet so need bigger prop.  Plane tested might be too heavy with bigger battery?  32 0zs with 2200. Did not have enough power to do vertical eights or reverse wing over. Trying to convert this plane and a fancy pant to fly regular pattern as well..   Bought a rock crawler pack 3000mah 3s 45c same length a little bit thicker and   1.9 ozs heavier. Will test soon. I am going to test it using a r/ c transmitter instead of a timer so I can set the rpm with the transmitter and can land the airplane when I want to check the battery to see how fast the battery is running down. Also can change rpm if needed eaiser. Will see how this works? The plane may be too heavy even with the bigger prop and higher c rating. Being able to land will allow me to check to see if the battery or motor is getting too hot? I don't think it will be a problem. The Mackey profile has a little more wing area than a ringmaster. It flew well with a glow engine if you could keep it running.  It was underpowered with a fp ..25 with 9/4 prop. Flew better with k&b .28 and 10/4 prop but not reliable.

So I test flew the mackey profile today with the 10x6 prop and the rock crawler battery.  Lap time was 4.7  seconds after about a minute of flying i landed and checked the battery and it was down to 65%.  Flew again for a short bit and lap time went up to 5•1 seconds which is too slow. Plane weighs 37 0zs which is way way too heavy.  Did not try to do any manuevers as it felt underpowerered.  This airplane has a little bit more wing area than a ringmaster so i thought it would  a good test bed.  It wiil fly the regular stunt pattern as i did it with a glow engine but it felt underpowered.  I cant go back to glow with it after modifying it for electric.  I dont think i can build a ringmaster light enough to fly well with electric at the altitude i have to fly at. •25 sized planes have to be very light to fly well at 5700` feet of altitude. I flew about 2 minutes and thelap time slowed down to 5.1 

I did not use a timer this time.  I used  a receiver and transmitter so that i could fly the plane and land it to check the battery as i used a timer and ran the battery down too far.  When the plane was flying at 4•7 seconds per lap it felt underpowered for doing manuvers with the throttle set at 9700 rpm. This was with a 10x6 prop. I used a 9x6 prop when i flew with the timer with same rpm.   I used a 3s 2200 30c battery with the timer setup and today i used a 3s 3300 45c battery with a 10x6 prop.  Battery ran down to 59% flying about 2 minutes.  I did not fly more as it felt underpowered and went slower so  no point in flying more. With the timer set up i could do inside and outside loopps but it felt too weak to try other manuevers such as vertical eight and reverse wingover. I wonder if the 45c battery runs down a lot faster due to the higher c rating? 

Keith Renecle flies at very high elevation (around 6000ft or so) down in South Africa.  You might inquire with him about successful motor/prop/battery combinations for his .25 sized airplanes.

Does high elevation effect electric the same as glow??

How could I contact keith renecle?

Here are some ways to contact Keith Renecle:
https://stunthanger.com/smf/profile/?u=1433
http://www.keithrenecle.co.za/Contact%20us.htm