Well I can tell you on the turbine side of this hobbie, one little air bubble can end your fun real quick as some modles of turbines (Jet Cats in my experace) can't take to many air bubbles before they shut off and force you into a dead stick.

Now to prevent this we mainly use a product in the US called a UAT, its a small 6-8oz fuel cell with a mesh materal vs a fuel line and clunk.

But from what I read in the UK, most peaple don't use these little header tanks, but just use the nice felt fuel clunks you can get at Lows, as it basicly dose the same thing, but the small header tanks, just like the jets and Helis use help prevent issue when flying with a lot of suden change of directions as most large (my 110in Krill Katan 60oz tank) dont have baffleing in them to keep the fuel next to the pick up. So the small tank kind of acts like a baffle.

So your options are;

1. make sure your current set up has flexable fuel line to help keep the clunk in the fuel, as some get very stiff qucily and will not touch the top of the tank when enverted.
2. Use a felt/filter pick up clunk
3. Add a header tank, very small tank.
4. stop flying 3D ,,,,, Ya right LOL

OOh yes some peaple reduce the size of the tank for 3D, but really your goal should be to make sure the tank is over the CG as not to cause an CG changes while flying, and if your motor cant handle the exstra few oz of weight for the exstra few oz of fuel, you may need a bigger motor or better set up.

Have fun mike