I have done a bit of a concoction in the past, if it called for 10WT, I have mixed 50:50 fox 15WT with generic 5WT.
From what I remember, Recons need 5WT oil. I didn't have any so I used PTFE infused 5WT fully synthetic engine oil.
To be honest, I dont believe its that much of big deal. They would like you to use the proper stuff but apart from warranty, its probably a load of wank.
Been running Chris king hubs for over 10,000km on finish line wet lube
Just make sure you put the right WT oil in the damper.