Old Yeast

I’m definitely having some rising issues. My last batch of bread took parts of 2 days to complete (some of it spent in the fridge), even with the addition of an extra tsp. of yeast. I use Fleischmann’s ADY Instant Yeast in the 1 pound vacuum pack. The yeast I’m using right now is probably over a year old, but it has been kept in the fridge the whole time.
I do think that its age is part of the problem and I have been aware of the slowness of this yeast for awhile and got around it by proofing it in warm water with a pinch of sugar added to perk it up. However, since I started doing a preferment and soaking another portion of my flower, I’m left with no water to proof my rather large yeast particles (about the size of mustard seeds). The texture of this last batch of bread was fine, no complaints as to the tooth feel/crumb, but I do wish the loaves had peaked about 50% higher than they did.
My plan is to try just doing a preferment with the whole wheat flour and when I’m closer to the point of mixing everything together, proof my yeast in the remaining 1/3 c. water with a pinch of sugar to get it going, then mix it with the dough conditioners, sweeteners and some of the flour to autolyse for about 30 minutes before adding the oil, salt and remaining flours. I’m hoping this will get the yeast good and infused into my dough and that it will rise like I expect it to. I’ll keep you posted.