Thats a good question.
I want to know that too.
Years ago i have converted my RC30's from 1 inch to 1 1/8 inch, but not with the original Pace headtube. That's because it was out of stock from Pace and they let me know there not going to make them in the future (that's what my Dutch Pace distrubitor told me).
So i bought a other brand 1 1/8 inch headtube and make it fit in the Pace crown, and worked very fine in my bike (Gazelle titanium).
But now i am not using the Gazelle titanium anymore and want to use the Pace RC30 for my Slingshot with has a 1 inch headtube.
The problem for me is, that the RC30 crown now has a hole that is to big to fit the original 1 inch headtube back in place for my Slingshot.
So a solution for me is perhaps to buy a RC35 in 1 inch and replace the legs for the RC30 legs.
Please someone let us know if the legs of a Pace RC30 wil fit into a RC35 crown. Thanks.