The height compared to Star Wars Luke seems pretty accurate.
Edit: got bored, thought id do some lame editing skillz. If you only have the Return of the Jedi Luke here's one:
Great progress on that custom!
So hyped for the r2 glad they didnt go with the two pack - already bought the r2 model kit but that looks promising! Thought for a second after checking on instagram that r2 has LED it might just be a simple turn on his holographic projector from red to gray.