You can put your snake in his lifetime cage right now. He's big enough. My guy is 4' 7" right now. He's about 1.5 years old.
We (Pro-Line owners) can help you out with questions if you go Pro-Line. Ed is excellent and he can help you too. Hit his web page and ask away!
I's also highly recommend talking to Bob at Pro-Products and so will Ed about RHP's for heating.
Best of luck.
Hey, AlexisFitzy, I sent you a message but your box is full so you won't get it FYI.