you could put him in a 1mx500x500 or something around that size, provide a few good hides and he'll be sweet, as a rule of thumb the tank should be bout one third the length of the snake
I kept my bredli's in little click clacks like those in my hatchy shelves below, for about 8 months. Then I moved them into another click clack but a bit bigger for them and some climbing toys. Now they are in 2ft enclosures where they will most likely stay for a couple of years. Here's some pics to show you..
I had my bredli in a 7lt click clack for about his first 10 months, he has just hit the 1m mark and I now house him in a 28lt click clack which I reckon will last him at least anouther 6 months then I will put him in his 900x600x600 enclosure, so by the time he gets in that he will be 18 months old!! Thought I would attach a flic of the enclosure Im working on for him!!