I am not a plumber. I would be thinking of switching to wax to minimize the gap. Normally with wax, you want to pre-position shims with no wax, lift the toilet, add wax and lower the toilet onto the shims and wax.
I would hesitate to suggest mortar. Maybe lay some saran wrap or other thin plastic on the floor, and put the mortar on that. The plastic would let the mortar release from the flooring if maintenance is needed someday.It may be easy enough to replace that high closet flange. Do you remember it being cast iron?
I would hesitate to suggest mortar. Maybe lay some saran wrap or other thin plastic on the floor, and put the mortar on that. The plastic would let the mortar release from the flooring if maintenance is needed someday.It may be easy enough to replace that high closet flange. Do you remember it being cast iron?
