Does a federal district court possess meaningful discretion to define 'proof beyond a reasonable doubt' in jury instructions?

QUESTIONS PRESENTED I. Does a federal district court possess meaningful discretion to define “proof beyond a reasonable doubt” in jury instructions upon request of a criminal defendant? Il. Ifa federal defendant for the first time on direct appeal raises a colorable claim of ineffective assistance by his trial counsel, with support in the existing record, should a Court of Appeals remand the case to the district court to conduct an evidentiary hearing rather than require the defendant to wait until a post-conviction proceeding under 28 U.S.C. § 2255, when he has no right to the assistance of counsel, to raise the claim? Ul. In order to convict a defendant of robbery of a business establishment under the Hobbs Act, 18 U.S.C. § 1915(a), must the prosecution prove beyond a reasonable doubt that the charged robbery itself had a “substantial” effect on interstate commerce — without considering the “aggregate” effect on interstate commerce of other robberies of similar business establishments? ii