qustion about plant height

I have a couple of blueberry clones that each stand 20" 1 is topped 1 is not I plan on waiting a couple more days but was wondering what i could expect for overall finished height? I probably have room for a five footer might get a little crispy up top though. And another question for blueberry growers should i top it I have heard that it is recommended , but I have also heard from some who say top only if needed (for space or whatever).
Once in the flowering room there will be a 400w hps a 400w MH and i use assorted cfl's for the lower parts of the plants

Hi Marcus

The plants will probably get 40 inches tall..

What is your lighting arrangement?

thats about what i figured but i have never grown blueberry before and didnt know what to expect. In my veg area I am using almost entirely 42 watt cfls I have 15 in various reflectors i also have 4-40 watt flouro tubes for clones. In my flowering room I have a 400 watt hps and 400 watt MH side by side and another 8 42 watt cfls for side lighting