Hi alheri,
Thanks for your question and welcome to the Forum!
The fact that you're almost finished with the Bible Trilogy is awesome. The PS Bibles do indeed provide a solid conceptual foundation that you can build on with practice sets and timed (as well as untimed) practice tests. As you may know, speed is a function of accuracy: you'll get faster once you start putting these techniques into practice. This is where the Full Length course homework comes in handy. It contains practice sets and drills that are much more extensive than those in the Bibles, so your FL course homework should definitely take priority. You really don't want to fall behind, as the course will move quickly and you'll have trouble catching up. Of course, if time allows, definitely work through the rest of the Bible chapters and practice questions. There is no harm in doing that
As far as practice tests are concerned, we normally wouldn't recommend adding them to your homework repertoire until Lessons 4 or 5. However, since you clearly have a solid grasp of most concepts, I see no harm in adding one test/week over the course of the next month... as long as you can finish all of your homework! If you do 1 test/week for the first month, then 2 tests/week for the second month, and up that number to 2-3 tests/week once your FL course ends, you'll end up taking about 20 practice tests altogether. This is what I would consider an ideal scenario as far as tests are concerned.
Hope this answers your question! Let us know if there is anything else we can help with
Thanks,