Yeast Question For Imperial Stout Kit With LME

I just ordered the How To Disappear Completely Imperial Stout kit from Boomchugalug on Amazon. I am excited so start this one up. It takes a long time but the idea of making my own imperial stout is very exciting to me.

This will only be my third brew, my others were much quicker. I have only done a Double IPA and a Coffee Porter, both were LME kits like this one.

So I have read that many people try not to use the mail order yeast that comes with these kits because it could have gotten damaged waiting on the doorstep or in the truck. And there was a comment on the yeast being used may not have had the length of life to fully ferment all the sugars in this big burly stout.

My plan is to got from chilled wort right into a glass carboy for the duration of its fermentation. I just got a blow off tube that I plan to use on this brew just in case.

I am concerned about using Safale-5 yeast (which is what I expect to see when the package arrives). Should I use a little extra? Perhaps there is a better product to use? The first taste is at 12 weeks, so I don't want this to go bad. I bought an extra carboy just for this one. It will be a nice winter stash if it goes well.

I will be bottle carbonating these after so I need to be sure there is at least enough active yeast at the end to properly, if not slowly carbonate the result.

Thanks for the help and happy brewing!