Meat serving and beef jerky

Instead of weight or palm-sized, I'd portion it per the posted nutritional content so you consume 25-40 grams of protein. I'd probably err towards 40 than 25 since you're eating jerky and not whey. You may want to consider a protein bar mid afternoon depending on how hard you're pushing yourself.

Apples to oranges but for weight lifters "According to the National Strength and Conditioning Association, a range of 1.5 to 2 grams per kilogram of body weight a day is optimal."

http://healthyeating.sfgate.com/much-protein-required-weight-lifter-2062.html

My jerky, which is very lean and very dry, is about 25% by weight of the original meat. Commercial jerky isn't as dry as mine, but should still lose maybe 70% of its original weight.

I'd agree with Ian. Go by how much protein is in a serving, not size.

Also, plan on soaking the jerky for a good time – it works, just needs time. And chop it up dry.