Transferring to no gi, simply takes time and trial and error. Keep in Parisyan studies with Gene LaBelle, one of the great no gi judo guys of all time. Without the guy judo is still not greco, some take downs are similar, but many more are still throws. No gi judo is more closer to no gi BJJ then it is greco
As BJJ includes both Judo tactics as well as Greco and Freestyle Wrestling, it has really very little that is exclusive to it's own syllabus as far as the takedown game. The tie ups needed to work Judo without the gi can mostly be found in Greco. They are not the same but very similar and I would suggest that anyone looking to better their takedowns seek out instruction from qualified coaches in these systems.