Try a little hotter load. 5.0/Unique is warmish, but most 358429s I've worked with have worked better with fairly hot loads. You're still below 38/44 levels right now. The earlier post about all 358429s not being created equal is dead on. Lymans fiddled with this design so much over the decades that nobody really knows what an original 358429 is supposed to look like.
