LM5145: LM5145 soft start time

Hello, 

We have urgent customer query regarding soft start for LM 5145.

Existing design is with 40msec soft start now customer wants to increase soft start > 500 msec ,

Can you please let us know your feedback and confirmation on below Queries ;

1. Is it possible to increase soft start > 500 msec? Is there any adverse effect on performance?
2. As per calculation we need  Css ~ 6.8 u F  , Is it OK ? Is there any limitation for max  Css  capacitor value?  
3. What impact it will have on other functionality mainly on overcurrent limit ( Rds on sensing  ) and hiccup during overload?

Thank you ,

Regards ,

Vikas