While time dilation is a real thing I don’t think it happens here, plus it doesn’t really fit with SW. In Empire I assumed the journey took much longer since the Falcon had to travel slowly, then Luke jumped into light speed and arrived a lot faster at Bespin. It also means Leia and Han had more time to grow on each other. At a guess… a month. Unless we believe that each piece of training is one day.
In TLJ I’m sure that 3 tests = 3 days = same 72 hours of fuel that the Resistance flagship had. I can’t be certain.
ROTS… 9 weeks? Who really cares.
I thought the cruiser had 18h of fuel left.