It's always best to test frame data with hit trades/clashes than by block punishing. Since block punishing may not always give you the most accurate results.
Another example Dogysamich, if you were to find a move of Talim's that is -8 on block, (and you don't know it's -8 yet), record Talim doing the move, then doing K right after. Then with the character that your using (I suggest Raph), and using their frame data as a guide, block the first move and then do a move right after. If you interrupt her K then do a slower move, if her K interrupts you then do a faster one. And once a move trades or clashes then you'll have your data. So in this case a i21 would trade with her i13 K, making the first move that Talim did -8 on block.
To find things on hit, what I do is record Talim doing the move, then a slow move right after (something around i20 usually), then test which of your characters fast moves trade with Talim's second move. So if your characters i16 trades with Talim's second i20, then Talim's first move is +4 on hit.
Also another important thing to remember when testing frame data is to never use the preset attacks that are in training mode, which are located in Free Style Settings > 2nd action > Attack. They tend to come out slower than if you manually record the computer doing it. It's better to not even use the 2nd action when testing, just record the move being done right after the other in one shot.