I'm not sure you should have started off with 6th level characters if you were a new DM worried about control. I'm assuming you have some material specifically aimed at 6th level. Then what about starting them with 4th level characters and given them normal equipment?
I think SeveredHead makes some good points, but I think "disaster" is overstated. I have a hard time really believing that the rather fuzzy guidelines in regards to creature treasure in the DMG actually produces anything close to an even distribution where every character in the party gets exactly X gp worth of magical treasure that it suited to their character class.
Things will drift away from balance from the start of the campaign, IME, unless you're sitting there with every treasure hoard saying "one item for the party fighter, and one for the thief, and, oh, two cleric items 'cause I know I got two cleric PCs, etc. etc."
Really- the GP/level chart and the CR values are useful tools, but there WAS A TIME when people DMed without using them as crutches and it wasn't so much of a disaster.
I don't have any problem with my low-magic campaign. However, it's a lot of work to modify gaming supplements and stuff if you want to use them and make them consistent with your campaign.