Well I only EV trained 4 Pokemon not 6 ^^;; But You don't have to go ALL the way immediatley. You can be a little flexible at times.
Let's say that I'm training a Crobat. Right now it's a lvl 5 Zubat baby. What I'm aiming for is attack and speed (luckily I did that in Sapphire making the attack EVs easy to get unlike Ruby which is pretty much screwed for life in terms of attack EV).
The best place in Sapphire to do this is the Underwater Cavern with nothing but other Zubats for speed EV at around lvl 30, and Mt.Pyre (low levels) for 100% Shuppet for 100% attack EVs only, at even lower levels. This means that all I have to do is just rare candy myself up to lvl 40+ or so then my Golbat/Crobat will be able to start picking off easy OHKOs on these Pokemon and begin EV training already instead of at lvl 100. Along the way I can earn a few levels as well as my Zigzagoon team works overtime for more candies.
The point is: you don't HAVE to reach lvl 100 to begin EV training. Start EV training immediately when you're high enough levels to OHKO the wild Pokemon whom you'll be harvesting EVs from. If your target is just Whismurs, then just rare candying up to lvl 14 and you can start EV training for hp already... Rare candy is used only to strengthen yourself so you can safely OHKO the wild Pokemon you're about to face for EVs without getting unnecessary EVs.
Try checking *very* often for Zigzagoon's items. Pickup works rather rapidly for me. After 4 battles or so with 5 zigzagoons, one of them will have pickup activated already. Also, I started saving for rare candy the second I started the game, so when I start EV training, I already had a stash load from previous saving ;p
Hope that made sense... O.o;