The form is here. If you don't know the highest level version of a weapon, you can check using these links:
Using the images, level requirements and rarity to match the item to the weapon if you can't use the names to do so.
If you've noticed, the links above do list attack stats alongside their grade. This does not mean your data is redundant. It just means that I have more sets of values to work with, should any of the values I currently have (from any source) be incorrect due to human error. However, if and only if you are going out of your way to look for data, I ask for information that the JP Wiki does not have (e.g. Mikazukimunechika, Wooden Sword).
Here's the spreadsheet.
Just to answer some questions:
- I need repeats (multiple data sets) of low level weapons or weapons with low attack, due to the game's rounding.