I'll defer to someone else with a better knowledge of J/suits.
I got my "off the shelf one" ages ago before I found this place and got the whole accuracy bug thing.
I've now got some great fabric and will shortly be getting a custom made Jump suit.
Which dickies? I don't know, but suspect you'd be wise to get 2 and use the second one as a donor for the sleeves and pockets etc.
Good luck.
Si