96 Van Diemen Clutch Release Bearing

My 96 Van Diemen FC has a Tilton 5-1/2 clutch. During my slave rebuild we discovered that the release bearing (Saab) is too large in diameter for the Tilton pressure plate. From what I understand this is the standard release bearings on VD and is intended for a 7-1/4 inch clutch. The proper Tilton bearing is 38 mm, which is too small for the VD slave piston. Any recommendations as to a source for the smaller bearing that works with the VD design? This car and the earlier VD's (90 thru 95) have a smaller bell housing/oil tank that cannot accept the tilton slave cylinder mod. so I''m kind of stuck. Prefer not to turn out a custom slave piston if possible. Thanks for all recommendations.