I'd have to agree with Julie and go one step further, a RHP with a nice proportional thermpostat would be the best setup for a wood cage IMO!!! There are two downsides to Ranco's....
Ranoc's are an on/off type t-stat so when on, the heat element sees full power. Will get much hotter than with a proportional.
Ranco's are mechanical contactors. Not often, not likely but possible to stick in the on position and roast the occupant!
If you are set on flexwatt, still go with a proportional t-stat. The flexwatt will not see full power except after a power off or maybe after a night time temperature drop situation. This will even out the actual flexwatt temperature.
As for placement, I would go for one end of the cage and towards the back of possible. That would allow for good temp gradients.
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Thanks,
Dave Colling

www.rainbows-r-us-reptiles.com
0.1 Wife (WC and still very fiesty)
0.2 kids (CBB, a big part of our selective breeding program)
LOL, to many snakes to list, last count:
26.49 BRB
20.21 BCI
And those are only the breeders 
lots.lots.lots feeder mice and rats 

