Admittedly this is crude, but the Duster designer told the builder to use 3 bathroom scales! Calibrate them with a known weight, then place a plank across two scales to weigh the main wheel with the most accurate scale used under the tail. Small errors on the main gear are not critical, but apply correction from calibration to all readings. Worked for the Duster and should be fine for other light ships like the 1-26.
JJ