I did plaster ceiling with the beams visible in in the living room, dining area, car porch and kitchen. I just lowered the ceiling a little bit sufficient to fix the led down lights. I didn't fix a plaster dome as this would require the ceiling to be lowered even more. There is cornice At all sides. Living room and dining has a simple box design and the original concrete ceiling is maintained at the centre but it's plastered ( to make it look as if it's a plaster ceiling and each of the 4 side is boxed. The result? Although the beams are still visible, it still looks good. It's a simple and elegant design. I do not feel claustrophobic as the ceiling is still high. My suggestion is not to lower the ceiling and conceal the beams especially in  houses where the original ceiling height is already  low and made worse with many beams which are very low such as in my situation.