The sandalwood trade was one of the last important Portuguese ventures in Asia, particularly during the post 1640 period, lasting until the end of the 18th century. The wood was highly prized in China due to its aromatic nature and used in ceremonies. The Portuguese were the leading supplier to the Chinese market until the 1830s, with most of it being traded via Macau. It is interesting, that this was really the last commodity that the Portuguese were able to control in Asia, beating out the Dutch. There were dangers of the supplies being exhausted during the 18th century, and during the early 18th century the Portuguese depended on an uneasy alliance of mestiço traders, called Topasses in Timor. Portuguese authority over these local rulers was never very strong, and often they were unwilling to submit to anything more than nominal suzerainty. In 1701-1708 there was an attempt to impose direct rule by Goa over Timor, with the Portuguese sending a royal governor to Lifau (located in the present-day Oecussi-Ambeno enclave). The Topasses were not only a threat to the Portuguese, but also to the Dutch in Kupang. The VOC actually considered abandoning Timor completely during the mid-18th century, due to the lack of revenue, and high cost of garrisoning Kupang.
The establishment of a trading factory in Western Australia would probably need to be around Southeast Australia where the aromatic Santalum Spicatum. It is not as suitable for carving as the wood found in Timor, but the roots of the trees of this species are the most valuable for the incense oil. The result being that the trees have to be pulled out by horse (or camel), rather than chopped down. This would require some sort of settlement be undertaken in the long-term. What sort is the question, the Estado da India governed the Indian Ocean territories and did undertake a plan to settle Mozambique during the late-17th century, sending several hundred families from the Azores to Mozambique. They might try something similar in Western Australia, with the intent being to harvest the trees, and establish some agriculture to self-sustain the fort. I would imagine that the 1670-1750 period would be the most likely for the establishment of factory/settlement in the region.