Great news that A90 has got to her new home! (And well done Dom!)
In answer to your question …. for me it would depend on how long the boat is going to be on the trailer and the extent of the works you plan. The way I winterise my trailer is to put wooden blocks under the trailer fore and aft of the wheels, and under the jockey wheel. This provides a completely stable platform and relieves the suspension. Ideally you need large blocks for stability. I use 18″ lengths of old sleepers – very rot resistant. I normally jack the front of the trailer first and place the blocks in front of the wheels, then jack and block the stern. This avoids issues with the jockey wheel.
The height of the raising from the ground depends on how long I intend her being on the trailer. During my protracted deck restoration I had the wheels clear but if the boat is only going to be on the trailer for a few months I lift just high enough to take most of the weight from the wheels. I know some people raise the trailer and remove the wheels before settling back onto blocks.
And I have worked on the boat without lifting the trailer at all. In this case I find a prop is required under the stern (to the deadwood) to hold the stern up. But the boat does move as you walk around!
Let us know how you get on.