I would get a 75 amp supply if the numbers that 9C1Driver posted. At 50 amps you don't have much headroom. I like at least 10 amps or more of headroom. JMHO.
There is a gent on EBay that a thread was posted about here, that sells a 75 amp power supply that appears to be well made and from all reviews, gets good remarks. Here is the power supply I am speaking of and the sellers name. Hope this helps. $172.60 shipped isn't bad for a 75 amp PS.
Just research it some before you buy as all I have seen are the reviews on EBay and a short review by one of the members here, who's friend purchased one recently. He hasn't had it long enough to give a long period review, but first impressions were good from what was said I am pretty sure. Again, hope this helps and good day.