ML-KG not much further than PH-KU
ML-KG is 1230 nm while
PH-KU is 1198 nm so only 30miles different which is pretty insignificant.
You are correct on the headwind though. Will be a challenge when winds are high. I would be surprised if they haven't allowed some fat in the system for a tech stop at Adel for the trip west on those occasions. AD-KG is only 960odd nm's so no challenge at all.
The HGW 100's (High Gross Weight) that XR operate can uplift 10.7 tonnes quite easily with 100 pax.
Last year an F100 went ML-PH direct with 100 pax for the AFL grand final so ML-KG should be within range on most occasions.