Lands found to be practicable of irrigation and reclamation by irrigation works and withdrawn under the Act of March 6, 1946 (43 U.S.C. 617(h)) shall be opened for entry, in tracts varying in size but not exceeding one hundred and sixty acres, as may be determined by the Secretary of the Interior, in accordance with the provisions of the reclamation law, and any such entryman shall pay an equitable share in accordance with the benefits received, as determined by the said Secretary, of the construction cost of said canal and appurtenant structures; said payments to be made in such installments and at such times as may be specified by the Secretary of the Interior, in accordance with the provisions of the said reclamation law, and shall constitute revenue from said project and be covered into the fund herein provided for: Provided, That all persons who served in the United States Army, Navy, Marine Corps, or Coast Guard during World War II, the War with Germany, the War with Spain, or in the suppression of the insurrection in the Philippines, and who have been honorably separated or discharged therefrom or placed in the Regular Army or Naval Reserve, shall have the exclusive preference right for a period of three months to enter said lands, subject, however, to the provisions of section 433 of this title; and also, so far as practicable, preference shall be given to said persons in all construction work authorized by this subchapter: Provided further, That the above exclusive preference rights shall apply to veteran settlers on lands watered from the Gila canal in Arizona the same as to veteran settlers on lands watered from the All-American canal in California: Provided further, That in the event such an entry shall be relinquished at any time prior to actual residence upon the land by the entryman for not less than one year, lands so relinquished shall not be subject to entry for a period of sixty days after the filing and notation of the relinquishment in the local land office, and after the expiration of said sixty-day period such lands shall be open to entry, subject to the preference in this section provided.