Teams are set to be composed of big-name players and sevens specialists.
New Zealand's Sonny Bill Williams is already playing full-time sevens but British clubs seem unlikely to release players until shortly before the Games.
"It is a very condensed programme and that puts us up against it," said Amor.
"The door is open for players from the 15-a-side game to put their hand up but the guys playing on the Sevens World Series, tournament in and tournament out, are in the driving seat."
In addition to 2015 Rugby World Cup-winner Williams, global names such as South Africa's Bryan Habana and Australia's Quade Cooper are keen on Olympic spots, while Wales wing George North and England back Danny Cipriani are among the home nations stars to have expressed an interest.
However, many of the players on show in Rio are likely to be sevens specialists who only play the abbreviated form of the game and have competed in the Sevens World Series for some time already,
England, Wales and Scotland compete separately on the Sevens World Series, but will come together to form a team for the Olympics.
And Amor hopes to hear before the end of the year if an application to field a Great Britain team at the second-tier Grand Prix Sevens series in summer 2016 will be approved.
The Grand Prix series consisted of three events last year and the 2016 finale will take place at Exeter's Sandy Park on 9-10 July - a month before the Olympic sevens tournament takes place.
While World Rugby's regulations state that players must be free to play in the Olympics themselves, clubs are under no such obligations to release their stars for the Sevens World Series, which begins on Friday in Dubai.
English side Wasps said in August that they would only allow players such as winger Christian Wade to join up with Great Britain two weeks before the start of the Olympics, in line with Premiership Rugby policy.
"We are working to see if there is a way of accessing players at the right time that works for both them and Team GB, while not compromising player performances for their clubs," Amor said.
"Ideally we get these players playing at some point on the Sevens World Series, if not then we put them into the Rugby Europe's Grand Prix Series in the summer and see if we can fast track their fitness and game understanding.
"It is a nice problem to have - how do we blend those players and teams together, the playing styles, the strengths of the individual players in what will be a short space of time.
"There is no nationality quota put in place.  The challenges we have are unique and it is about working through them to send the best team we can."

Posting a picture of a letter addressed to "Mrs Clegg" on Instagram, she noted the "irony" of the situation.
The event, on 8 March, is designed to "celebrate women's success", she added.
Ms Gonzalez Durantez is a lawyer specialising in international and EU trade law.
She wrote: "The irony of being invited to speak at an International Women's Day event to celebrate women's success, addressed to me as 'Mrs Clegg'."
Ms Gonzalez Durantez set up the Inspiring Women group, which recruits women with successful careers to visit and speak to girls at state schools in England.
This is not the first time she has criticised the way she is perceived or described.
Last year she told Marie Claire magazine: "I find people say of me 'She wears the trousers' and as you can see, it is true, I have very nice trousers.
"Or if my husband and I share the school run, it's me who has forced him, dragged him away from his work.
"But when people, or in my case the media, are using that label on you, they are not saying you are strong, they are saying you should get back in your box. You should make the dinner and have his slippers ready with a gin and tonic."
Coach Simon Amor says getting hold of 15-a-side players and integrating them in time for Rio has already put Great Britain's sevens team at a disadvantage ahead of the 2016 Olympics.
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Miriam Gonzalez Durantez, whose husband is former Deputy Prime Minister Nick Clegg, has complained after being invited to an International Women's Day event in her married name.