PPP Vs Amai Mask: Amai Mask scales directly above Prisoner, he wins by default without the need of being handsome
Tanktop Master Vs Amai Mask: TTM and Amai Mask are around equal in AP but TTM is slower (Massively Hypersonic) than AM (Massively Hypersonic+). TTM however is stronger in Lifting Strength, good advantage but having higher skill and speed + Regeneration should give this to Amai Mask
Metal Bat vs Amai Mask: Since Metal Bat starts at his Base, Amai Mask might also win against him considering they are in character (AM would just cut him before Fighting Spirit kicks in). Base Metal Bat is weaker (High 7-C) and slower (High Hypersonic+). If Amai Mask doesn't kill him in time he is screwed
Pig God Vs Amai Mask: Same as TTM, similar scaling, Amai Mask is faster and more skilled, however PG also has Regeneration. Kinda Inconclusive, having higher speed is a very important factor, so I'll give to AM
Zombieman Vs Amai Mask: Amai Mask stomps and blitzes however it's Zombieman, AM has no way to negate his Regeneration in the (really) long run
Child Emperor (Brave Giant) Vs Amai Mask: They both match in AP and speed, but Child Emperor is FAR more versatile while AM only has skill and regen for him
This is as far as Amai Mask can go in my opinion. I'm not saying he gets stomped by everyone else but the fights should be way more decisive than these above. Note that I'm not counting Watchdog Man, Metal Knight or King
The rest are kinda evenly matched, the obvious outliers are Blast, Tatsumaki, Flash, Silver Fang and Atomic Samurai
Flash directly defeats Bang and Atomic Samurai, then loses to Tatsumaki who gets shitstomped by Blast, who wins the tournament
Now, I'll try a prediction here: Monster Amai Mask. Let's take his WC scaling and apply to the manga, which is:
Full Power Monster Amai Mask > Full Power Pesky Clown >= Base Monster Amai Mask > Dragon Pesky Clown >>>>>>>> Base Amai Mask = Baseline Dragon level
Which makes him able to basically one shot someone who one shot a baseline Dragon level, would that be High Dragon ? Kinda
With that gap, I can see him winning against basically every S Class with the obvious exceptions of Blast, Tats, Flash, Bang and Atomic (considering he uses the sun blade, otherwise good fight)