Hopefully this can be kept up-to-date by me or any other people who are willing to share with the community. The pointers I post are valid for Nippy's Fishbot. I don't know if other bots use the same format so YMMV.
[1/30/2019]
Tested working on two different accounts. I will calculate the other offsets later today if I have time. Alternately if you want to use the fine instructions provided by @phj280600 then see the snippet I pasted below.
Pointer=0x00FD9168
WaterOffset=0x7FC+0x14+0x164+0x3C4
ChocoOffset=
LavaOffset=
PlasmaOffset=
StateWaterOffset=0x71C+0x2E0+0x6D8+0x550
StateChocoOffset=
StateLavaOffset=
StatePlasmaOffset=
Calculate your own offsets like this!
Step 5. Now that you have the pointer for water catch use a hex calculator to calculate the last offsets. So in my experience there is a pattern to the last offsets try adding or subtracting either 268, 26C or 4D0 to the last offset and see if it works.
I recommend trying to get the next offset of STATE first. The State Offset is what is used to detect liquid type. The reason you want to calculate STATE first is that it will be easy to see if you got the offset correct because the bot will indicate the liquid type instead of saying unknown.
Here is my interpretation of @phj280600 instructions. Google a HEX calculator. The first Google result from calculator.net works fine. Input the last value from the StateWaterOffset line, e.g. 550. Do not include the 0x part. Now add 268. The resulting hex value is 7B8. Now update the Nippys ini file for StateChocoOffset=0x71C+0x2E0+0x6D8+0x7B8 (this is an example only, not tested!). Reload the Nippy's config and test in chocolate. If the bot detects you are fishing in chocolate you can move on to LAVA, then PLASMA. For lava take the last value of the StateChocoOffset (62C) and add or subtract 268, 26C or 4D0 until you find the value that works. Last, for Plasma take the last offset value of Lava and do the same calculation until you get a working result. Now move on to plain Offset, which is "catch". Do all the same steps but now when you test in-game if the lure is pulled in then you got the right value.
***If your first calculation does not work try adding 26C or 4D0 to the last value of State Offset. If none of those work then try subtracting 268, 26C or 4D0 from the original last value of your State offset.