Personally, I don't think it's possible to tell exactly how strong Page One is nor is there anyway to really know exactly how strong Kamazou is.
Page One while we know he's a headliner, we can't tell if he's really strong to begin with. Sheepshead was also a Headliner, Speed was a Headliner, Holdem was a Headliner and none of them have really looked particularly strong.
Among the headliners, the only ones who have really stood out are the Supernova being Hawkins, X Drake, we can assume to be just as strong as Hawkins, but we've yet to really see any formidable headliner as of yet.
The problem with ranks is it's almost impossible to tell how strong someone is with rank. It's like the Shichibukai title, some are as weak as Buggy/Crocodile and you have some as strong as Mihawk who is up there with the Emperors and Admirals. Any rank that is below the highest of ranks makes it difficult to gauge strength accurately.
The only way to gauge strength as far I'm aware accurately is:
- By certain Titles. If they have the title of Admiral or Emperor, at this point, you just have to assume they're ridiculously strong. Also, If they're Yonko commanders, you have to assume they're strong, but how strong can vary from being fodder to the Emperor or being almost as strong. Besides these, any rank that isn't a Commander of an Emperor, Emperor or Admiral makes it hard to really determine how strong a person is.
- How difficult it took Luffy to defeat said character. This is another way to determine strength and why we can easily say Katakuri is undeniably stronger than Joker, both have fought him and we know Katakuri was the much more difficult fight.
- Comparisons. If they were compared to being as strong as a particular character or stronger. Ashura Doji is said to be as strong as Inuarashi/Jack, so we can gauge strength in this manner too.
Outside of these, I'm not sure of any reliable ways.
General compliments are also not great indicators of strength. Joker went on to compliment Sanji's kicks only to literally fodderise him. Luffy said Hyouzou was strong, and then after that, Zoro more or less 1 shots him.
Luffy said Fujitora and Inuarashi were strong when he initially met them, yet we know he's called someone who was 1 shot at Fishman Island strong. Generally, compliments are not very reliable.
So, between Kamazou and Page One, can't tell how strong either are. Unless it's stated that they're as strong as x-character at this point or said to be close in strength to an all-star rank, I guess their strength lies in the balance.
Disclaimer: These figures are not accurate, juts examples thrown to make a point.
On another note, one of the difficulties in defining strength too is terminology. How is strength defined? If we refer to strength as physical capability, that makes sense. However, the mistake that arises is winning fights can often be used to claim a character is strong even though winning fights doesn't always indicate physical capability.
Caesar is not exceptionally strong, but he can win fights because of a dangerous ability.
So, I guess judging a character comes down to understanding how strong they are physically and how difficult they are to fight depending on how they fight. If I had to assess character, it'd be based on 2 criteria:
- Physical capability (Scale of 1-10 for example)
- and Difficult Fighting Against (DFA) (Scale of 1-10 for example) - Would depend on ability and its complexity. Simple abilities would not be great difficulties.
Examples
Caesar
- Physical capability - 4.5 - He's not all that strong.
- DFA - 6 - He has a dangerous ability, and therefore can defeat strong people by taking out the oxygen.
Luffy
- Physical capability - 8.5
- DFA - 3 - Gomu Gomu no Mi is not a really difficult ability to fight against, the difficulty is a physical one mostly.
Cracker
- Physical capability - 7.5
- DFA - 8 - Ability is incredibly reliable.
This is how I currently view Sanji.
Sanji pre-Raid Suit
- Physical capability - 6
- DFA - 1 - No Ability or Special Equipment.
Sanji Post-Raid Suit
- Physical capability - 6
- DFA - 7-8 - The Raid Suit changes the battle dynamics drastically. While he may not have grown stronger to me, he' a very very difficult fight with the Raid Suit's invisibility, durability and all round capabilities.
I don't think Oda has done much to make Sanji stronger, but with the suit, he's been made to be a much difficult opponent to fight.