Delgado was neutered at 10 months, my contract with his breeder required by one year old. It wasn't hard keeping him but his drives did peak several times, if you're committed to a LOT of exercise and training it shouldn't be a big issue. They do need a outlet.
Otherwise anytime after 6 months is ok
For maturity most people say two years old for males. As for the "male macho" look - that's more genetics then hormones
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - Male GSD - born Jan 26, 2012
Koda & Zazu - 5 year old male cats
Alex - Male Cocker Spaniel (rescue) - RIP Cuddlebug 2007-2010