Yes. Always best to go by volume, although the weight by volume will be the same as the actual weight of real backpowder, plus or minus a bit depending on tolerance/accuracy of your volume measure. With any of the substitute powders (Pyrodex or T7 for example) always use the volume measurement. They are designed to be a substitute for blackpowder by volume, not weight.
I have a TC Hawken in 50 and over the years I’ve had good luck with 50 grains as a plinking load and 80 grains for hunting so the starting point of 60-65 grains will give deer sized game accuracy to about 100 yards without much trouble if you know where to hold and know your gun.
All good advice here. Every BP gun is different. 2 TC Hawkin rifles might like different loads. After much experimenting mine likes 60 gr by volume 2F with a 20 thousandth patch and 490 ball. Yours might prefer 50 or 70 gr with a 10 thousandth patch and 495 ball. Lube also makes a difference. Mine likes a liquid lube. Yours may prefer grease. Keep experimenting. It's all part of the fun.