EUREKA - Roman army troops

[Paullus Scipio]

...on re -reading your earlier posts, I came across a possible small error.......

In book XXIV 13, in 214 BC, Marcellus sends 6000 foot and 300 cavalry to Nola. In 211 BC, at Capua (Livy XXVI 17), Gaius Nero was assigned a force of 6000 infantry and 300 cavalry. In 207 BC Livy (XXVII 43), Gaius Nero marched with a force of 6000 infantry and 1000 cavalry, to northern Italy.

You seem to be implying that these are evidence for 6,000 man 'legions' but Gaius Nero's force was a picked force from his army of his fittest troops. "....From his whole force, Roman and Allied, he selected the best men, 6,000 foot and 1,000 horse.." - Livy.
In other words a composite force from his entire army, not a 'legion', and certainly not evidence of the strength of legions at this time.
Similarly, Marcellus force of 6,000 'foot' and '300'horse' sent to Nola is almost certainly another example of a 'picked force', not a legion (else Livy would have said 'legion').
Gaius Nero's army sent to the relief of Spain after the deaths of the two elder Scipio's is also a 'picked force' "...Senate passed a decree assigning to Gaius Nero a force of 6,000 foot and 300 horse, to be chosen by himself from the two legions he had at Capua, and an equal number of infantry together with 800 cavalry from the Allies of the Latin confederacy. Nero embarked these troops at Puteoli for Spain..." - Livy.

Shipping space, and urgency were clearly the factors here - Nero couldn't embark his entire consular army.

Clearly, none of these examples are evidence for a 6,000 man legion.