Players have concerns but remain open-minded about the England and Wales Cricket Board's plan for a 100-ball competition, the Professional Cricketers' Association has said.
The format was proposed in April as a way to attract new and younger audiences to the game but has had a mixed reaction from players and fans.
Player representatives met with the ECB on Tuesday and while PCA chairman Daryl Mitchell described the sitdown as a success and "very informative", he also said that many "unanswered questions" remain.
Following the meeting with ECB chief executive officer Tom Harrison and Sanjay Patel, managing director of the new competition, Mitchell told BBC Sport: "There is a lot of detail to be decided and we are more than willing to work with the ECB on that and hopefully we can play our part in shaping the new competition.
"One of our biggest concerns is the timescale. We are two years away from this tournament and we are still not even set on the format.
"Things need to happen quickly.
"We need to get more details in the near future, not just how this competition looks but how the rest of the playing schedule will look for our players, when player drafts are going to be and pay bands etc.
"There are a lot of unanswered questions in terms of how the format will look but we have had assurances we will be part of that process and they (the ECB) are keen to stress it is still a concept, an idea, not a done deal - which was good to hear."
Mitchell said "another concern" was that England Test players like captain Joe Root and Ben Stokes will be on international duty during the competition.
"They'll be allocated to a team for marketing purposes but won't be playing," he said.
However, he added the ECB made the point that "this new audience won't necessarily know who Stokes and Root are anyway".
England director of cricket Andrew Strauss has said the 100-ball proposal, which the ECB wants to introduce from 2020, is aimed at "mums and kids in the summer holidays".
England bowler Stuart Broad praised the concept's "unique selling point", but BBC cricket correspondent Jonathan Agnew questioned what impact it will have on the four-day County Championship.