Hi Fanny ,
https://community.justinguitar.com/t/boom-bass-with-licks/349225/10?u=roger_holland
Previous requests had been made here, I would also love 4 seconds in advance because then I can join the first bar 
But Richard allready checked this with the match my sound, but I think Mathieu , Iand some more mean this with the play alongs .
Greetings