I’ve been reading (and this is primarily for my online notes) that it is wise to throw in some dry yeast into the bucket when bottling and mixing priming sugar for bigger beers. The reason being that after a couple months in a secondary, the yeast settle down and don’t get siphoned up into the bottles. Here is a good forum link on the subject.
Sounds like a lot of folks use dry yeast US-05 if the secondary lasts more than 2 months or more. Here’s a good how to video on rehydrating dry yeast.
Also, I bought a stir plate from this guy who also sells on ebay. I bought it direct. Works great and a great price.