The arbitration tribunal shall, so far as is permissible under the law and practice of the seat of arbitration, have power to fix all procedural rules for the holding of the arbitration including discretionary power to make orders as to any matters which it may consider proper in the circumstances of the case with regard to pleadings, discovery, inspection of the documents, examination of witnesses and any other matter whatsoever relating to the conduct of the arbitration and may receive and act upon such evidence whether oral or written strictly admissible or not as it shall in its discretion think fit.