I checked all of my wildcat books with no referance to a 35 Johnson. I did find an internet listing for a 30 Johnson Special, but there was no info at all.

In the hayday of silhouette there were alot of gunsmiths that converted XP's to improved or shortend cases necked up/down to fit the short XP action. The 30 IHMSA comes to mind, it's a 300 Savage case necked down to 7mm. It was an Elgin Gates creation and very popular. There was also a 7mm International that was very close to that, but a little different. Anyway there were alot of these similar cartridges with small variations to the case and the smiths name was applied. He made the dies with the reamer. If the dies come with it you are all set. If there are no die you need to cast the chamber and see exactly what it is and go from there.

The 30BR and the 30DC are another set of cases that come to mind, very similar but the chamber is different.