Hi there and welcome!
You 7 blade roast is a Chuck. I would definitely aim to finish 4 hours before you want to eat and tightly double wrap in foil and then tightly wrap in 3 bath towels. That will hold it for 4-5 hours no problem.
RickNessly
had a similar suggestion as well that works no problem.
Main thing to know about your cut of meat is that it is done ONLY when it is tender. Not by time or temp with your cut of meat. Now, temp will tell you when to start checking for tenderness.
At about 200F Internal Temp (IT) of the meat you can stab all over with something like a kabob skewer and when it goes in all over like butter then it is tender and ready. If not tender ALL OVER then let temp rise another 2 degrees or so and check for tenderness again. Done when tenderness tests pass :)
With chucks I smoke to 180F IT and then I wrap in foil with about 2oz of water/beer/wine/broth or whatever liquid I want to add. Chucks can dry out on you so I do this.
***(Important) Why 180F IT??? Because if you wrap beef too early it comes out tasting like roast beef rather than smoked beef BBQ. This is extremely disappointing given how much money, time, and effort went in to trying to make BBQ beef and not oven roast tasting beef.
Smoking unwrapped to 180F IT will ensure you get BBQ smoked beef and not roast beef.
Why do people say to wrap at 160F IT then? They do this to speed up the "stall" where the rise in meat temperature slows down due to the meat sweating.
To me flavor is all that matters. I'm not trying to speed up a stall, I'm trying to make the best BBQ I can enjoy. My solution is to just add more time to the smoke to deal with the stall, simple.
I wrap at 180F on a chuck because it ensures amazing smoked BBQ beef flavor AND keeps it from drying out. Nothing to do with the stall or speeding things up.
With a whole packer brisket I don't even wrap the thing I smoke unwrapped the whole way. A chuck and IMO a brisket flat both benefit from being wrapped due to drying out.
I hope this info helps you out with your smoke there. Each meat has it's quirks and you just have to prep and experience it to adjust and make it better each time until you nail it consistently :)
Best of luck on it, I think you got a good jump on time :)