You consider $3,000 dollars in credit card debt reasonable?
Credit card debt almost always means you are making unplanned purchases that you can't afford.
The cost is interest rates, which for credit cards are not only higher than planned purchases, they also contain agreements that the credit card companies can change and fees that they can use to increase their profits at your expense. The game is heavily tilted in the credit cards companies favor.
To me reasonable debt means you have thought about the expense, and negotiated a good interest rate. With a little smarts and self-control you can lower interest rates by saving money for a down payment.
Reasonable debts include college loans or buying a house. Both of these are things you plan for and are investments-- they pay off in the long run.
Think of how much money you waste by carrying a $3,000 debt even at the best rate, without getting snookered with fees (and the vast majority of us get snookered with fees) you are talking hundreds of dollars a year in interest rates.
By simply living within your means, you will save much more money than your credit score will. Start by simply not carrying credit card debt.
On the other hand, I don't carry cash or pay by check for anything I can pay by credit card. I too have approx $100,000 of available credit and typically charge about $3,000/month. But then I zero balance my cards at the end of each month, never paying interest fees, late fees, or annual fees. This allows me to get up to 30 days free use of my money.
Having and using credit cards for all purchases (major and minor) is an easy way to keep track of expenses and doesn't necessarily mean that one is not living within their means. Zero balancing the accounts each month takes willpower and commitment but managing our accounts this way over the years has given us an impeccable credit history.
I only carry two personal cards and one business card. One of the personal cards is a high limit card and is the one I use for most purchases. The other card is a low limit card and is only used for internet or over-the-phone purchases. Very little damage can be done that way if my number is somehow captured and used by someone else.
To the original question, whether you have one or two cards with large credit limits, or six cards with smaller limits isn't important. If you are carrying multiple cards because you needed the extra credit then negotiate a higher limit (and lower rate) with one or two of the companies you want to continue to deal with and cancel the rest. Your credit rating is based on your payment history as much as it is on your available credit.
If you are paying finance charges, then I would strongly recommend reducing your overall debt to the point where you can zero balance your credit cards at the end of each month.