Samour said he might seat as many as 12 alternate jurors — an unusually large number — in the event any of the 12 regular jurors is dismissed for hearing outside information or other reasons.
"The court cannot keep the jurors in a bubble, completely sealed off from the outside world," the judge said.
Samour has said 5,000 potential jurors will get a summons and that he expects 3,200 to 3,500 to respond.
Holmes' lawyers had also asked the judge to scale back the heavy security that has been present during 11 months of pretrial hearings, saying it would be "extraordinary and unnecessary" during the trial and would prejudice the jury against Holmes.
They also objected to deputies standing so close to Holmes in the courtroom that they could hear his conversations with his attorneys.
Eight Arapahoe County sheriff's deputies usually stand guard in the courtroom during hearings. Others watch from the rooftops of the two courthouse buildings and in the parking lot.
Samour said four of the deputies in the courtroom will wear uniforms during the trial, and any others will wear street clothes. He also said they will keep a reasonable distance from the defense table.
The judge overruled the defense objection to having deputies on the rooftops and in the parking lot, saying they're necessary to protect Holmes and the public.
Samour said Sheriff Grayson Robinson had agreed to the hidden harness and tether for Holmes and the plainclothes deputies in the courtroom. Samour added he trusts Robinson's expertise and will heed his advice.