This is from the Marvel Directory, maybe it can help. I also thought this would be a great battle.
Height: 7 ft.
Weight: 750 lbs.
Eyes: Blue
Hair: White/blonde
Other distinguishing features: An unusual percentage of body mass is concentrated in Guido's upper half of his body
Strength level: Superhuman Class 50; can range upwards to an unknown limit through absorption of kinetic energy.
Fighting skills: Formidable hand-to-hand combatant, relies on streetfighting techniques Special skills and abilities: Talented musical comedy actor and stand-up comedian.
Known superhuman powers: Aside from the above listed attributes, Strong Guy has the ability to absorb kinetic energy and to use it to enhance his physical strength up to an unknown level.
Special limitations: Strong Guy cannot store the kinetic energy he absorbs for very long and must physically expend it within 90 seconds. Otherwise, the energy will physically distort his body permanently. Strong Guy is in constant physical pain. He is near sighted and wears corrective lenses.
Honestly, my money is on Strong Guy here. He is actually one of the very few Marvel characters that has been able to move the Blob with his own power. I don't believe that Thing can boast as such.
Besidses, anything that Thing dishes out, Strong Guy absorbs and then releases it back at Thing. Enough of that punishment and Thing will go down.