Truth be told I don't use dumbbells much. But I find there is good carryover from the barbell exercises . Especially comparing bars of the same thickness. Gym dumbbells tend to be very thick in the UK and static. Forget a spinning OL dumbbell . Your numbers will be much higher on an OL dumbbell of 1/4 compared to a nearly 2 inch thick static non-spinning dumbbell. Personally In find it takes less skill to clean or snatch a dumbbell compared to a barbell. My best barbell 1 hand power clean is around 60-70kg, dumbbells about the same. I stopped doing them due risk of injury ,as I persued my 1 rep max (totally unncecessarily) . I have started doing them again at the gym and I can barely manage a 50kg dumbbell ( at around 1.75-2 inches ) They are still very valuable to do but it is like comparing apples and oranges.
I have around 140-145kg bench press compared to perhaps 55kg -60kg thick db with a bit of a dip. So to answer your question it won't be close to your barbell bench press unless your never bench press. But even then not everyone has the same ratios.