Brian,
I think you need to determine exactly what you want from this plane. Is it a weapon for carving patterns in the sky or a sport ship? I'm going to assume it is a dedicated pattern ship. (Now this attitude gets me in trouble, in that I tend to think there is no place for sport leisure in a competition applications. Go all the way or go home)

I would practice your flight routine (no sport flying), time it, land and measure the amount of fuel you used. Add 10% for safety. This is the minimum you need. It should be less than 12 oz.

Now the Pump was developed to allow one to gain a lot of power from the bigger choke area of a bigger carb. The larger the choke area the less power is lost to a restrictive carb. But and this is a big but, the fuel draw is drastically reduced. There is very little pressure drop at the spray bar as the velocity of the air is rather slow (The pressure differential between the engine and the tank vent is very low) and as a result there is little fuel flow. The pumps job is to offer more pressure to the carb so more fuel can flow into the engine. What I'm trying to show is that the pump does not add power but rather the power come from less atmospheric pressure being lost to the carb's venturi (choke). There is a very linear relationship to inlet pressure and power . This is why closing the throttle (choke) cuts down the power. Or conversely the more you open the choke area the more power (Duh). Now as far as the engine goes that's it

Now on the airplane as a system there are two issues here, fuel head pressure and balance trim. Staying with the feeding of the engine at various attitudes the ability of the fuel to flow to the carb and/or pump changes pointing the nose down and the fuel pours out the fuel line, Place the aircraft level and the flow slows until it stops level with the fuel discharge. Point the nose up and no fuel flows. This is called fuel head pressure. There is a lot if the fuel level is above the carb's discharge and little or even negative pressure if it is below. Add or subtract this pressure to the atmospheric pressure and it becomes clear why the engine needs so much mixture adjustments from a nose up verses a nose down. Now the smaller the carb's choke area the greater the atmospheric pressure differential (constant if the RPM stays the same). Therefore there is less total pressure (Tank vent to spray bar) change with the small choke verses the large choke as you point the nose up of down. Note this is the case with or without a pump again if looking from the tank's vent to the fuel discharge port (spray bar). Now the fuel pressure changes to the pump inlet as the tank is raised and lowered. So there needs to some kind of regulator in the circuit to compensate for this variability at the front of the pump so that the pressure is kept constant to the carb. Now if the fuel tank is kept close to the carb there is little stress placed on the regulator to keep the fuel pressure constant to the carb as there is less change in head pressure to the pump inlet. So far so good.

BUT BUT 14 fluid oz of fuel can account for a lot of mass change in the aircraft. Now put all that in the front of a 7 lb to 9 lb plane and you have a lot of trim changes you need to make from first take off to the last landing. Now place the tank on the CofG and re-trimming during flight is drastically reduced (there still needs to be some, as the angle of attack now has to be lowered as the total weight is about 12 oz less weight) sounds good. But the further the tank is away from the carb the more the regulator must work to maintain even flow. This is because the pump is adjusted for the worst condition (nose straight up) tank very low and far away from the carb. Now point the nose straight down and the regulator must deal with the extra flow from the added head pressure (gravity) and the over zealous pump!

So what to do? I'd like to see you keep the tank as close to the engine as possible (this is why most pattern ships actually have a rather short nose). And learn to use the CofG shift to your advantage. That is do the smooth axil rolls at the beginning of your routine and save the spins and post stall maneuvers for the end when the aft CoG will make these maneuvers easier. Now the problem with this is that you have to keep a little airspeed on landing. We kind of frown on a snap maneuver at the end of the runway as a closing salute!

Now I know this is just what you didn't want to hear the KISS principle! This is the best way to start pattern with a simple machine. Small carb, the smallest tank to fly the routine, a long pipe to keep the noise down and add rather constant muffler pressure to the tank. By the way this pressure tap should be at the high point of the pipe NOT in the header or manifold. This is a good place to find a good balance between peak pressure and constant pressure. Muffler pressure can be thought of as an atmospheric boost to aid fuel flow. It is a poor substitute foe a pump or proper tank and choke sizing.

Now if you want to flirt with that 20% to 10% I was mentioning earlier do think about placing the tank at the CofG and run as large a fuel line to the pump as possible. Use a regulated pump and a small choke carb. You should be able to find carb bodies that fit the carb boss of the engine case and have various choke areas (Interchangeable barrels) and have in flight mixture controls. There really should be no need to go with a choke that is bigger than 8.5 for your first pattern engine. That great CMB has an 7 mm choke IIRC.

All the best,

Konrad