Is there a nominal troop number per base (eg base=128real men) or just a percentage of army type thing

There is no stated representational scale.

So next daft question can I have a 2base TuG of Theban Sacred band, especially if i play with myself or a friend ?

What consenting players do between themselves is up to them 

FWIW the list allows a 6 or 8 base Sacred Band TUG in Maximus which would become 4 and 2 in Magna and Pacto respectively.

so that is a no . I know they can be in bigger units. wanted to know if a 2 element TuG is allowed/workable as a flank guard type unit to cover the main Theban "pike block" as it roles over the Spartan line

2 base units are allowed even in Maximus - not many but there are a few out there.

The Theban Scared Band should be used to spearhead the attack as they did historically.

Have seen 2 versions of the Theban Sacred Band 1 they are at the front of the main body, 2 they deploy as a separate unit , so I guess you pays your money and takes your choice.

I am not aware of any evidence for the Sacred Band deploying as the front rank of a phalanx, I believe they always fought as a single entity.
Deploying as a front rank was a DBM tactic to have Sp(S) supported by a second rank of Sp(O) if I remember.

Richard

Thanks, I may have poorly expressed myself when used the phase "flank guard"