You should be able to pull the converter forward into the crank and against the flexplate. In other words, even unbolted from the flexplate, the converter bolt lugs should be touching the flexplate. The flexplate should not be bent onto the converter when bolting it together.
If necessary, it is possible to use spacers. But it usually means that the converter snout is too long or some other issue that is causing the converter to bottom out in the back of the crank before touching the perimeter of the flexplate.
I have used 2 flat washer between the flexplate and converter when using a midplate. I don't recall if I still use one washer now in a regular configuration or not. It's been a while since I've had it apart. But you may need to use a longer bolt to insure enough thread engagement.
The converter does have a bit of "travel" on the input splines. But it should also not be allowed to bottom out on the transmission shafts/in the pump.