Agree with this, I find it tough when handling my specimen strikes for the 1928-1936 series and comparing it to the proof, very tricky to spot what the proof really brings to the table. Compliments to the chefs for striking of circulation coins during this period i guess?
Had a CGS 88 1935 sixpence and comparing to my PF65 1936 there are just the slightest of differences to look out for, mainly jagged edges but even then.
Agree with the crowns too, so many out there that are not proof and would need to be spectacular for me to consider it even if a TPG said so