I have shot PPG products for 30 years and I dont much care for their Concept clears , I have shot their European Global Line for the last 12 years over DBU & DBC with excellent results !!!!!!!
I like Global as it buffs like butter !
Getting ready to switch to PPG's AutoColor Aquabase Pro . and their clears used are the European style clears , the reducers feel oily when you get some on your hands unlike US style reducers they evaporate quick and dont have that feel .

Dau 82 was an excellent clear in its day , but you cant get it anymore as it doesnt meet VOC Compliance . Shot tons of DAU color and DAU clear , used DAU 82 over DBU when it was first introduced in 1986 .

PPG makes DC3000 & DC 4000 clears and have 3 temp hardners , no reducer is required , they are nice too . you may try those .