Fundamental Analysis - Data Choice

This is a question for those who keep financial models on companies.

As we all know, Resmed is one of those excellent companies that deserves modelling in order to drool over the vast amounts of shareholder wealth that they have created for 20+ years.

Since they report in US$, my question is - do you prefer to complete your models and subsequent valuations in US$ or in AUD$?
Data providers such as Morningstar convert their historical data into AUD - so using this for historical analysis can be somewhat misleading. Wild swings in growth rates can be largely due to the exchange rate fluctuations. This leaves the option of putting up with this problem, or to identify the approximate exchange rate used and reverse back the changes.
The other option is of course to use data straight from RMD filings.

A further question (which is somewhat a whole other discussion) would be, if you choose to use an all US$ modelling and valuation method, yet invest in the ASX listed CDIs - are you converting your valuation to AUD using the spot rate? or are you happy to maintain your valuation and follow the US listed stock, preferring to ignore the gyrations of the exchange rate?

Happy to hear some thoughts,
Cheers