Found this a couple of days ago and have been playing with it. Looks rock solid.
Monte Carlo sims, timing models etc etc etc.
Seems to be free (not seen any paid only features) and works really well with US based ETFs/Stocks.
Use EWH to compare your allocation with a broad HK based index (not sure what the correlation is with 2800/HSI)
https://www.portfoliovisualizer.com