Macho Brace is never better under any circumstances excepting ones where you don't have access to the power items.
EV reducing berries should serve nicely if you're not one hundred per cent certain that you EV trained your pokemon properly. If you are certain, perchance try a new calculator. I've found this one to work remarkably well, similar to Metalkid's but much more user-friendly:
http://waitingforseedot.appspot.com/ivs
There are several issues with them if you're overly fussy, though most are moot unless you're planning on battling professionally with said pokemon. First, you can't change a traded pokemon's name, which can be a bother if you're trading with people from Serebii's IRC who have a penchance for naming their pokemon 'pooface'. Second, if you haven't completed the game your pokemon might not listen to you, though this is, of course, easily remedied by just beating the bloody game. Third, your pokemon may be hacked. Things to watch for: Impossible abilities, perfect IVs (pokemon obtained by abusing the RNG are still legitimate, though) 252 EVs in all stats, or certain shiny wondercard pokemon. Last point, and this is a major one, the pokemon you're getting might just plain suck.
Is it a viable lead if my flawless areodactyl has rock head ability instead of pressure?
Pressure is mainly used over Rock Head because most Aerodactyls don't use any recoil-inducing moves. Though, running an Aerodactyl without pressure might go a little ways towards misleading your opponent into assuming you're running... Double edge, maybe? Either way, Aerodactyl is by no means going to stall even an 8PP move out of PP, so you may as well keep the one you have.
Your substitute has an HP bar separate from your pokemon's, equal to 25% of your HP, regardless of what you do with your HP in the following turns. Basically, it's as if you're in a double battle and your opponent is down to his last pokemon and your incredibly frail partner insists on using Follow Me until it's dead. And, you can revive him. And he leeches your HP when you do. I hate metaphors.