The only information we have is that Jaylon said he is running a 4.4/4.5.
I didn't take Jaylon's tweet to NECESSARILY mean he was running a 4.4 40 now but possibly that he was simply saying he was getting some of his speed back and referencing his previous 4.4 40 time (I suspect the last time he ran a 4.4 40 was a while before he put on a lot of weight, like high school or freshman years). If he ever ran a 4.4 at 235-240..well that is pretty darned impressive. But anyway, I took his tweet to me focusing in and improving my speed right now despite still running a 5.1 40 but basically saying "I'm getting closer to the speed I once had" back in college when I could run about 4.5.
I'm a big fan of Jaylon's now, he's clearly a fantastic person and determined to overcome adversity and a real RKG you want to pull for. That said, I'll be honest, I didn't see the reason for as much hype as he got about being a top 5 pick prior to the injury. Clearly an amazing athlete with a rare size/speed combo but I never would've pegged him top 10, didn't see a Kuechly-like LB. Jaylon's most tackles in a season was lower than Kuechly's lowest year. I could see Jaylon having a monster impact and be a clear upgrade over Hitchens as a run and hit, don't think just go-find-the-ball guy as long as Sean Lee is Qb'ing the defense, but I never saw top 5 or even 10, esp considering how the draft values the LB position. Of course, if he can be another Jordan Hicks (and conversely knock Wentz out for a season) that'd be great.
Of course this coming from someone who didn't see Dak as anything more than a backup.
I will claim Elliott though, I called him as OROY before the 5th pick of the draft was made haha.
but to the OP question, I'm going with a 3-3.5.