Hello,

See column 12 in the following act ;

https://www.icsi.edu/media/portals/86/bare%20acts/stamp%20acts/Kerala.pdf

Also a local lawyer will be in a better condition to tell you the exact stamp payable 

Stamp duty is not required during award pronouncement. It s only required during enforceability of the same as the decree of the Court u/s 36 of Arbitration & conciliation Act and 47 of CPC

The kerela stamp act prescibe stamp duty for award.

https://www.icsi.edu/media/portals/86/bare%20acts/stamp%20acts/Kerala.pdf

Under the act in coloumn 12 you will find the duty applicable .

Section 17 of the Kerala Stamp Act requires that all instruments chargeable with duty and executed by any person in the State of Kerala shall be stamped "before or at the time of execution". An award is an instrument chargeable with duty. (Vide Article 12 in the schedule of the Stamp Act

2) stamp duty varies from state to state 

3) local lawyer can guide you as to stamp duty  payable 

Kindly contact any local lawyer. 

It appears that arbitrator is inclined to partially allow your claim 

Section 14(1) of the Arbitration Act it was clearly the duty of the arbitrator to inform the parties of the amount of stamp duty payable in the award.
the stamp duty is calculated at roughly 0.1% of the value of the property to which the award relates.

Section 33 of stamp act prescribe that award may be written on stamp paper though SC has held it is not mandatory only directory.

The stamp duty and the court fee are state subject and depends on the nature of business it is used.

You may enquire about this locally.

As opined in the previous post, since this is a local subject, the claims made by you and the opponents may make difference in the stamp papers to be used for award, hence it would be better that you enquire the same locally.