No. Your revolving utilization has a significant impact on your score. Revolving utilization is balance(s) / limit(s). Assuming you don't rack up a high balance, the high limit will probably help your revolving utilization.

Don't base need on the amount you intend to spend. General advice is keep revolving utilization under 30% but lower revolving utilization is generally better. I don't need to spend $200K but having total limits in that range allow me to keep my revolving utilization at 6%.

It's possible but we can't say for certain as we're not underwriters for creditors. Any creditor is going to have a limit on what the creditor is willing to extend to a given credit profile. We have no idea what AmEx would extend to you or how your $28K Chase card impacts what AmEx would extend to you. You won't find out until you bump into these limits. If and when you do you can reduce limits and/or close accounts if you want to comply.

There are too many other unknowns that play a part in your questions. A $25K Chase card didn't prevent me from getting another $25K Chase card, a pair of $25K of AmEx cards and so on but YMMV depending on your credit profile and income.

Here's a starting point. It doesn't contain everything. It is just a starting point.
http://www.myfico.com/crediteducatio...yourscore.aspx