When is comes to dome pressure, there could be multiple issues involved. It may be that the valve in question is mis-sized (too large, too small). Also you may try out a load spring. Bascially, just a very low pressure spring in the dome that helps to facilitate dome pressure. If it does not...
Visit CWFC.com/farris and register for the sizemaster program which will allow you to properly size the relief valves. This is one of the best programs available for relief valves.