I am trying to get everything sorted for my new wheels before they get here in a couple of weeks. Is there a way of sorting the spoke size based on this information or do I need to wait until the rims arrives/ask for further info?

29″ rim
ERD 603mm
Depth 20mm

Hope Pro 2 evo front and rear 142 X12 rear and 15mm front

ERD is all you really need for the rim. Hubs are standard and should be already in most a good spoke calc XL spreadsheets/online calcs. That said it’s always better to measure stuff than rely on suppliers data

http://spokes-calculator.dtswiss.com/Calculator.aspx

the PCD etc for Hope bits is readily availabel from a google search,

Another usefull spoke clculator

http://www.wheelpro.co.uk/spokecalc/

I would second what has been mentioned above, it is always best to measure the rim yourself prior to buying the spokes.

Ok cheers I will do the calcs and then wait for rim to double check.