I found a tip from a general x-plane forum and solved it to LES Saab 340. You can increase both taxi and landing light enormously by changing the following parameters from present 1.0 up to 9.0 in the custom_lights.obj. The attached pictures are with 7.0.
Notice values 7.0: LIGHT_PARAM airplane_taxi_sp 0.0 -0.25 -0.19 7.0 7.0 0.85 0 1500 0.9239
Remark: the value 1500 above was changed from 1200 to the latest 1.6.5 update, but I could't see any difference.
Notice values 7.0 and do this to L/R landing light: LIGHT_PARAM airplane_landing_sp -0.745 -1.11 -2.545 7.0 7.0 7.0 0 2000 0.9396
Please enjoy the night flight!
