I'm 5'11" and 'variable weight

(around 220)
Clip-on's without rear sets WILL make your back hurt
Tews19 is worse than me, I only have L4/L5 messed up
I find clip-on/rearset combo pretty good for my back
You will develop a 6-pack and take some weight off your wrists (if you out of shape your wrists will hurt, particularly if you have bad ergonomics)
As for clip-on question, I made my own mounts with 10degree angle but it wasn't 'steep' enough so I cut new bars out of some old 'cruiser style' steel handlebars. (cut about 2" down from first bend)
Now I have mufti-adjustable bars

I just checked, they are set at 20 degree angle, but, I think I'll buy some different bars and go a bit 'steeper (probably round 25~30 degree's)
Here's a pic from when I started showing original bar height.
Clip-on's are about 10" lower and 7" further forward. (this was before I rode it and tilted them further down)
