My shade of studio fix is still out of stock

NW15
I have some left but what can I try and use thats similer?
Should I buy some select foundation from MAC in the shade I use? I hear its a sheer foundation, If its too sheer would it be ok if i was to mix it with the studio fix that I have left to make it last me till more is in stock?
Or does anyone know what the Hyper real foundation is like?
Any opinions? or anyone tried mixing?
Thanks