Stu, K6TU, has provided us with a nice propagation tool. It creates prediction charts for all bands from 10m through 80m - based on your real location (Maidenhead locator like JO31 or FM19). You can also select from some typical antenna farms on your side like "Vertical", "Tribander/Wires" or "Big Gun". The tool will help you to get an idea when to reach Timor-Leste on which band. You can use this service for free and generate your individual chart (no login required, but please consider to check out Stu's other services offered there).
Here is an example of what you get from K6TU's propagation tool for 4W DXpedition.
Reproduced with permission – K6TU, 2023
Please use our contact form and let us know what you think about this service. We'll be happy to forward your feedback to Stu, K6TU.
To understand what are the difficult signal paths through the polar regions, look at the Great Circle Map around Timor-Leste. There will be challenges to reach W1, W2, VE1, VE2, VE9, VO1, VO2, other countries in the Arctic and also some parts of South America. Having understood that, we'll try to be on those bands at those times which can provide the best chances to work those difficult regions.
Picture taken from DXAtlas software, (c) Alex, VE3NEA.