At the units I worked all the lateral separation charts were listed with the maximum height to which each particular chart was valid - this to take into account aircraft slant height distance from the DMEs. With the arrival of modern radar the charts went the way of the dodo.
To cater for any radar unserviceability a readily accessible table is available on position to enable controllers to work out separation distances based on angular differences from an aid and aircraft height - not quite as flexible as the 'old' separation charts, which quite often had entry/exit distances from an area of conflict based on different DME's - but good enough to allow the 'now procedural' controller to work something out whilst the radar was being fixed.
I must admit that I enjoyed those old procedural days. Felt a great deal of satisfaction at the end of the shift.