Farnsworth timing can be used in word training, the configuration is just different. Another user already asked your question and Fabian (DJ5CW) has explained it in this thread:
https://lcwo.net/forum/3035
dj5cw:
Farnsworth is possible in Word training, by setting the "minimum character speed" above the speed. E.g. character speed 20, speed 10wpm, then you will start with Farnsworth, and as you move up, the spacing will gradually become smaller, until you reach 20wpm, where you will no longer have Farnsworth timing.
73
Fabian
So it is possible, though I am not sure it is a good idea to use Farnsworth timing in word training:
1) Many experienced users recommend getting rid of Farnsworth timing as soon as possible, because real morse code on the air is always without Farnsworth. That is what you will need to be able to understand in the end.
2) In lessons and code groups you are learning the recognize individual characters. In word training and plain text training on the other hand, you are learning to recognize the sound of entire words. With Farnsworth you will learn the words with incorrect timing, which might be hard to unlearn later.
I guess you can use Farnsworth timing in word training for now, if you feel that it helps you. Just don't hold on to it for too long, especially once you know all the morse characters well enough and your brain starts remembering entire words.