Lift and Drag Coefficients using load cell data
I guess your design is a conventional one.

One approach could be integrating two load cells in between the tail and wing sections.

You can measure drag force and moment. And the moment may help you estimate the tail lift (with some serious assumptions though).

If space is a concern, you can try building a scaled model (2:1?) to test a larger model. The resulting forces and moments must be corrected for Reynolds effects.