The Flimflam, 100%, no contest, especially with 4/5 pilots. In a jumpy battle of heavy cav, the TargComp'd LPL is king.
The Thor doesn't really have a range it can fight at to eek out an advantage.
Except for the ranges of 10-15, inclusive, where the Thor II is responding with every single gun it has but the Flamberge has ER PPC and LPL only, and exactly 21 hexes where the Flamberge has the ER PPC only and the Thor II has two Ultra/5s and
two LRM launchers for some reason I mixed up which Thor II had the LRM-5. Fortunately, it's damage doesn't meaningfully affect any of the numbers later.
At skill 4/5, it's still the Flamberge assuming both jumped 5 hexes to get where they're going, leaving it at 11 and 9 versus 12s across the board. Every point of skill improvement applied to both 'Mechs pushes things further from the end of the bell curve, and the Thor II starts to come out on top of expected damage trades right around
1/2 between 1/2 and 0/1 (huh, the LRM-5 did change things a bit), but the gap closes
very quickly from the extreme.
Expected damage at 4/5: Flamberge ~4.03, Thor II ~1.31
Expected damage at 3/4: Flamberge ~6.67, Thor II ~3.92
Expected damage at 2/3: Flamberge = 10, Thor II ~7.83
Expected damage at 1/2: Flamberge ~13.47, Thor II ~13.06
Expected damage at 0/1: Flamberge ~17.08, Thor II ~19.58
With 4/5 pilot it's still the Flamberge's fight to lose, but
literally any reduction in to-hit numbers that applies to both units will close the gap. Which is really just bell_curve.jpg. And I think I'd still take the Thor II against all comers or an unknown enemy.