Consider this a WAG, cuz noone can tell you what YOU want/need, but the .40 springs would probably be fine.
I'm closer to 210/215 with gear (I wear a LOT of stuff..around 180 tare), and I found the .40s to be perfect.
They don't need a ton of preload. Example (again...just because it works for me doesn't mean it will suit you), I changed my preload recently from 8 to 3mm and found the forks to be much improved. 110mm oil level. Valved by mx-tech.
From CDave (3-3-03):
It’s the 1996-99 0.38kg/mm XR400 springs that are interchangeable and commonly used in 1995 to 2003 KDX200/220s.
From racetech:
'96-99 xr400r 43mm showa .38
'00-02 xr400r 43mm showa .40
'H' model kawi spec:
'00 200 kdx 43mm kyb .35
**********
SET THE SHOCK SAG!!!
Start at 100mm (another imo), change to suit.
**edit**
BTW, I know you asked about forks, but they kinda work WITH the shock, 'eh?
Here's a quick shock setting summation:
Basically, compression needs to be SOFT enough (clicks out) to absorb impacts without jacking your arse, HARD enough (clicks in) to take as large an impact as you're going to give it. Rebound needs to be FAST enough (clicks out) to be ready for the next impact (not 'pack'), SLOW enough (clicks in) to keep the wheel on the ground during the rebound process.