As I said in my first post of this thread, we have actual events where Superboy has been shown to be superior. Yes, we have examples where characters have
stated Mon-El is superior. But my rule of thumb is actions speak louder than words.
Mon-El and Tharok agreed that a battle between Mon and Validus would end in a stalemate. Later, Superboy bowled Validus' legs out from under him and held his own against the entire Fatal Five for a time.
Ultra Boy's mind in Superboy's body vs Mon-El in a head-on collision: Mon-El was knocked down not Superboy.
When Superboy, Mon-El, Ultra Boy, and Wildfire used their invulnerable forms to block the nega-bomb from destroying the Earth, all the others were knocked out. Superboy was the only one left standing and conscious.
Given that canon evidence, I'd give the physical superiority to Superboy too.
Yes, Superboy, Mon-El, and Ultra Boy have learned to hold themselves back when using their powers to both avoid killing/harming others and to avoid collateral damage.
But Lar and Jo spent most of their lives before become powered as normal people. They fully know the strain and thrill of pushing themselves to their peak. They spent a lifetime learning reflexes where normal exertion and straining is their norm. Holding themselves back is not a natural state for them and they easily have a lifetime of normal reflexes to fall back on.
Kal-El spent a lifetime having virtually no experience of such things, unless you count those scant two years as a baby on Krypton. He spent most of those same years in a world where other people are like wisps of smoke to his super-strong, invulnerable hands, where most structures and matter are far more fragile -- to him -- than eggshells are to us. His natural state is to hold himself back in all circumstances and to use his powers at even relatively normal levels is completely alien to him.