RE: Sodium chloropalladite and Ziatype, now on to making AFO

Has anyone made their own ammonium ferric oxalate (AFO) from ammonium
carbonate and oxalic acid? What was your experience?

The "formulary" at B&S states to make AFO, simply nuetralize oxalic
acid with either ammonium or ammonium carbonate. I had the later and
mixed equal parts (by weight) together into about 100ml of distilled
water. After the fizzy stuff stopped, I vigorously stirred the
concoction and then poured through a coffee filter, allowed to strain,
and then spread the resulting white paste onto a glass sheet to dry.
Is this an appropriate way to "nuetralize" or I'm likely to have
missed a step or messed up the desired AFO?

thanks

Darryl