I guess you could look at it this way: If it's easy to cut and shape - it's easy to warp and bow. Hahaha

Poplar can be great for bodies in the tone dept. I made a neck out of Poplar once for a 6 string(3 sets of 2 strings) 28" scale Dulcitar that started to bow on me. Had to cut down to 4 strings to stop the bowing. The neck was a 3/4" thick Poplar with 2 - 1/4" Red Oak laminations and a steel rod for a trussrod. 

There's a guy on the TDPRI Guitar Forum that regularly makes necks out of Poplar with success, but He uses adjustable trussrods.

Also used Pine on a 25" 4 string neck with non adjustable trussrod and laminated fretboad. Won't do that again, even the headstock bowed on it.

Red Oak, Maple or Mahogany is the way to go for necks. IMO

Deltagroove.com makes great necks for CBG's in complete or you finish modes. Check them out some time.

Depending on what material your neck is made of, is to  how high your string action is at the last frets. Whatever wood you use there'll be some bowing of the neck that will raise the strings.

I always use Red Oak for necks with a non-adjustable trussrod on my necks. That's usually stable enough for 4 to 6 strings. On my bridges, I usually mount a bolt on a block of wood that can be trimmed or exchanged for a bigger one if needed. Things don't always turn out the way they're planned, so having a way out of the mess is good rather than starting all over again.

Will the bridge saddles have adjustable height?

Saw your email in the strummers and dulcimers group. We can't reply back from the emails which is annoying and I don't knw why they won't fix that.

You'll want your bridge/saddles to be about 1/8th" or less above the last fret on the board for fretted gits unless you plan to occasionally play some slide. If you want to play some slide, you'll need more height, but your the only one that can say how much because it depends on your playing.

Hope that helps. Not a lot of talk goes on in that group so you may want to ask those type questions in the CBG 101 group's comment wall.

Hi Rooster

Can't find you question about setting up bridge.

Put a pencil mark at the centre of each end of the fingerboard,lie a steel rule on these marks then put a third mark at the bottom of the box where the centre of your tailpiece will be(or the centre of your box where your bridge will sit if you aren't using a tailpiece)

Wayfinder did a thread about using nails for frets, It's how the old blues guys did it. Do a search around the site and you'll find it.

Thanks for the friend add, can never have too many.

Hi, thanks for the friend add, glad you're enjoying the music : -)