A Chrony Chronograph still costs about $80.00. Mine has served me well now for many years. At the current cost of gas, some trucks can't be filled with gas for that price. Its a bargain. And its available to anyone who can afford to be shooting. Check Sportsman's Guide catalogue for pricing on the Chrony. Competition Electronics, out of Rockford, Illinois, has the next level of Chronographs, at a range of 120-200 dollars. When you want to spend more than that, you go up the Ohaus lab grade Chronograph.
If you still can't have a chronograph available( a group of shooters, or any gun club should consider buying a chronograph for all to use, BTW.) by all means, spend $15.00 to buy Dutch Schoultz' Black Powder Rifle Accuracy System. He developed this system before Chronographs were widely available, using the reading of both POI and spent patches to tell what is going on with a particular load. The material is a fascinating read, well written, and will be a reference source you will refer to time after time, because you seem to learn more every time you read it.
http://www.blackpowderrifleaccuracy.com/
is Dutch's website, with contact info.
HINT: With this information, AND a chronograph, you can work up an accurate load for any rifle in record time. You can change powders, grades, brands, etc. and use the chronograph to find the " Sweet Spot" in velocity to make that new load shoot as well as the first.