magnifying glass/loupes used for alignment

Hi guys,

am sure you guys can help me out.
what loupes or magnifying glass are you guys using to help aid in the alignment of your carts ?
if using loupe, how many x magnification is recommended ?
if using magnifying glass, how many x if recommended.
any on-line stores you guys can recommend ?
Anyone here using PEAK Loupes ?

thanks for the inputs...

Noli