I just decided to look at the resistors I have got on RS, 157-566.
They are in fact wirewound and I had a look on their datasheet.
10 times commercial wattage rating for 1 second
5 times commercial wattage rating for 5 seconds
2 times commercial wattage rating for 3 minutes
If I use 500R resistor to charge then it will be 10X for short period, only 5x after 500ms
Do you think these resistors could handle 100x for maybe 50ms. If I use a 47R resistor it will charge to about 220V in only 200ms, fully charged in just 800ms.