Hi krayzc-RCU,
Thanks for your info, pictures and link. It certainly helps me to understand alot better what it really takes to virtually stop the CG from unintentional changes on the fly. The only thing is, it'll require times to modify the fuse in order to move the tank - quite a fair bit of work. Thanks again.

Hi Jack Hyde,
If I understand correctly, if the model is balanced with empty tank initially on the ground, then towards landing period with almost an empty tank, the model should still be flying very nicely. When the tank is full during take off and subsequent flying around nose heavy, the model will be stable. It is only when things like hovering are done, that the CG is likely to become sensitive.