What problem is the soft start solving? I've captured a number of current and voltage waveforms with a scope on 400's and 700's and the inrush current does not exceed the maximum surge current of the rectifier. Yes I've used a total of 40,000uf on 400's and 30,000uf on 700's. In addition, the curves for the standard 10 amp fuse will allow it to open before any inrush current could hurt the bridge rectifier.
If it is felt that a soft start is needed I would suggest using a phase angle control circuit as opposed to resistors/thermistors and relays. Phase angle control is the principle of operation behind the old style incandescent light bulb dimmers and uses a triac for the control. 9 out of 10 people believe that a dimmer is just a rheostat. Actually, a rheostat is used, but it controls the firing (turn on) of a triac.
There is a phase angle controller IC, TDA1085, that incorporates all of the functions needed to make a softstart. The datasheet has a PCB layout. Although I didn't check them out there are listings on ebay for the 1085.
I used the TDA chip to make an automatic softstart on an outdoor garage light. It phased on at dusk and off at night and the bulb lasted for years.