Sounds like you should be able to update to 4.50. <- this is just my suggestion as 4.53 is still being tweaked worked on.
As far as which ver cfw to choose I can only suggest from what I've used / experienced.
There are many current developers on here that have cfw's out. I recommend Rogero. Now updating can either be done by XMB or Safe Mode (PS3 Menu with many options such as rebuild database).
If you have more questions please don't hesitate to reply back.
Others please feel free to add anything that I might have missed out as I'm sure it will help him decide.