From a FICO standpoint, a large CL may not help more than a more moderate CL.
However, from an LO review, the higher CL is better as long as it is not to a level that they feel you present too much potential debt risk.
The reason: If another creditor felt you were worthy of a larger CL, then this speaks to your credibility.
If you have adequate income and savings to cover your down payment, maintain savings/emergency and pay off debt that you need to....then YES YES YES go for the 10k secured card.
If you are not using the CL more than a few hundred bucks, the $10K is still in savings and is part of your financial portfolio because you don't have an offsetting debt against it. While it is "securing" the card, this isn't much different than a CD. You can close the CC at any time and withdraw your savings (minus card balances).
So, the $10K secured card adds to savings, gives you a good CL and CC reference, creates a needed TL and will provide you great utilization percentages when you only use it for expenditures that you PIF each month, maybe leaving $50 as a balance.
Remember: FICO is important, but your CR contents are just as important, and in many ways more important.
