You describe your climate as tropical - not sure what that means in practical terms. Important because when planted out your plants get your climate - you can´t control it.
In their habitat, the Mexican desert mainly, summer is the rainy season. Winter is sunny but dry. The plants get a chance to rest and ripen the growth sustained in the summer. With my own collection - which are in pots, they go in a cold frame in winter - they are kept dry for 3 months, but get plenty of light. I think this rest period is important, and contributes to the good results I get with L. williamsii.
To be a bit more specific, L. williamsii are found in northern Mexico, and southern Texas, where they are acclimated to a limestone soil, and sparse rainfall, 100 to 300 mm a year (!), concentrated in the months of June July & September. They are, of course, succulents which are designed to swell and thus store water in the few months when it is available. If they get too wet, they can, and will split - this happened to two of mine in March 2012 when we had 200mm of rain in one day (pic). (They did make a full recovery.)
I have severe doubts whether any desert cacti will be happy if deluged with 1000mm in one month. As well as the splitting, rot is always a likelihood if they get too wet. However, you can only try it and see with a couple that you are prepared to lose. We all lose a plant now and again, however good a grower we may consider ourselves. Good luck to you.