nova ss frame and under carriage semi-gloss black

[1968 nova ss]

Guys ,I restored a 1968 nova ss L-34 car about 10 years ago and used the PPg with a flattening agent.. with good results,,but had an issues with the shelf life on the dx685 flatteneing agent.....I am currently working on another 68 nova ss matador red car...what is good product and mixing formula that is out there today.I like the look of the semi -gloss look,not too shiny,but not definetly the flat look... am almost ready to spray the under carriage of the car ,it is currently in DP 90 now,Thanks,Chris Teed