Yep, just try to see what feels natural to you before you buy them. Then get an idea of how much pullback and rise you need and the width.
I run Pro Taper SE's on all my bikes, but any good quality aftermarket bar is good.
Here's a link for ya. They have sizing charts for all their bars
http://www.rockymountainatvmc.com/p/43/53/218/947/-/8613/Pro-Taper-SE-7-8%22-Handlebar/HANDLEBARS
Pro-Taper SE 7/8" Handlebar Sizing Chart
Bend Width Height Pull Back
ATV High Bend 32.00" 6.30" 3.94"
ATV Low Bend 32.00" 5.50" 3.30"
ATV Mid Bend 32.00" 5.90" 3.00"
Carmichael Bend 31.50" 3.00" 2.17"
CR Low Bend 31.50" 2.80" 2.68"
CR Mid Bend 31.50" 3.23" 2.36"
CR High Bend 31.50" 3.74" 2.45"
Factory Suzuki Bend 32.00" 3.63" 1.85"
Henry/Reed Bend 31.50" 3.70" 2.17"
Honda Mini Bend 28.75" 4.60" 1.97"
KTM 50 Bend 25.50" 3.15" 1.75"
KX Low Bend 31.50" 2.80" 2.36"
KX High Bend 32.00" 4.25" 3.07"
Kawasaki Mini Bend 28.75" 3.71" 1.97"
Raptor Bend 30.30" 5.63" 3.41"
RM Low Bend 32.00" 2.91" 2.17"
RM High Bend 31.50" 3.23" 2.87"
School Boy High Bend 28.10" 3.46" 1.77"
School Boy Low Bend 28.10" 3.07" 1.85"
Suzuki Mini Bend 28.75" 4.00" 1.97"
Windham/RM Mid Bend 32.00" 3.90" 2.13"
XR50 Bend 28.50" 6.75" 1.75"
YZ Low Bend 31.50" 2.64" 2.76"
YZ High Bend 31.50" 3.31" 2.05"
Yamaha Mini Bend 28.75" 3.90" 2.28"