How much yeast for bottling?

Been a while since I've been here. Good to see y'all.

I have a pale ale that's been sitting untouched in a fermentor since September. No oak barrel or anything fancy schmancy, just a PET bottle fermentor held at 20C for nearly 7 months. I sampled it days ago and it tastes ... not bad. I'd like to bottle it. I suspect it will either be the best or worst batch I've ever brewed.

I figure the yeast (US-05) have likely died out or at least gone inactive. If I want it to carbonate, I'm pretty sure I'll need to add yeast. Without, I suspect carbonation would be inconsistent, at best. I've never done this before. How do I measure how much yeast to use? Is the amount of dextrose affected? 

I'm otherwise open to suggestions; what would YOU do with a pale ale that's been aged half a year?

Many thanks for your help! I trust everyone has been well.

Greetings Mofo and welcome back!  My suggestion is to use CBC by Lallemand and to go ahead and prime a bit higher than you normally would.  I'm guessing there is no residual CO2 left in the brew so any carbonation will have to be added / created.  CBC is intended for this purpose.  The dry contents of the package will condition 5 gallons (19L).  I don't believe you need to be concerned about the amount of yeast you use.  Instead, your concern should be the amount of sugar and perhaps one of the other brewers can offer more advise in that regard.

Good luck!

Thanks Keller. Happy to see that I can get CBC here in China. Ordered a couple packets last night. I'll do more research on the amount of sugar to use. I suspect it might be no different from calculating CO2 volumes when packaging any other beer.

Greetings mofo - a concern I would have is in regard to the residual carbonation (or lack thereof) in the beer before priming sugar is added.  There is a certain amount of residual CO2 in beer after fermentation is complete.  The amount is residual CO2 is determined by the temperature of the fermentation.  Being your brew has sat for so long, that residual CO2 most assuredly has escaped.

http://byo.com/resources/carbonation

The above link may help determine the amount of residual that may still be in the beer and what you may need for priming.  Personally, I would add a little more priming sugar than what's recommended for the style.  But, how much is a "little"?

Good luck!

Welcome back, Mofo! 

Sierra Nevada filters all the yeast from their beers and then adds back 1 million yeast cells per ml of beer for carbonation.  This is the best and only reference I could find to how much to add for such a purpose.