For a Physics project (regarding the properties of sound waves), I was required to build an instrument. I built what I thought was a ukelele. It is approximately three feet long, and the body is in the shape of a coffin. The finish is a yellow to red sunburst finish done with wood stain. So, I went to my local guitar shop and saw that ukeleles are much smaller than my instrument, but guitars are much bigger. It's sort of a hybrid between the two (it only has four strings). Now that I found out that it's slightly too long to use the average ukelele string, I decided to use regular guitar strings, with the tuning of the bottom four strings of a guitar.

Now, everything on the body is finished, except for the frets and the strings themselves. I need to know: what are the guidelines for doing a fretless instrument?
Does the height of the strings above the fretboard matter at all? Would nylon or steel strings work better for a fretless 'guitar'?

If someone with knowledge in the area of fretless instruments could help me, that'd be great.

Thanks and sorry for the wall of text.
Quote by XibanezedgeX
Well nylon strings would have less wear on the wood then steel.

Nylon would work better in this case.

And that whole thing sounds awesome. post pics!
Gibson SG Faded
Epi VJ Stack

Quote by Øttər
Whenever I clean my guitars, my family wonders why it smells so good; I say that I exude a fresh citrus scent from hidden orifices.
They stopped asking
Alright, I'll make sure I use nylon.
So, there's not any special thing I've got to do to make the fretless notes sound good? I mean, won't they sound like they're being palm muted, or not make any noise at all?
And I'm already going to make the nut deeper... I made the nut, and it ended up being about an inch too tall. Everything on this guitar (except the tuners) is homemade, so it'll be a small miracle if it works. Either way, I'll try and post pics in a few days.