Moving a tank with anything heavy in it is always risky. The weight can cause stresses on the tank that can weaken seems. You may not know until one day....
Ive moved an 84g tank once and emptying it seems the best, safest way. It's not a bad thing in that it's an opportunity to fix a couple of things that you didn't like, clean some dirty equipment, etc... Re-assembling the tank isn't so bad since your already have all the kit, know where you want it, tubes are already measured and cut and you have a working bio filter.
Unless there is something unique about the conditioning of your water, you don't need to save a lot of it. 50% is plenty, much less should still be fine. Depends on how different your water is from your tap water. If not very different, don't worry about how much you save. Instead, just refill with water at a temp close to your target temp to ease reacclimation.
The process is straight forward. Fill containers with some water, remove plants, trim roots and lay into a container. If you were having critter challenges, take the time to dip them, to clean algae and snails. Put hardscape that you remove on a tarp somewhere.
After much of the water is gone, catch the fish. Put them in your containers, add an airstone if the move will be spread out over a day,or two. Not necessary, but if you have the parts, put them to use.
If you remove substrate, the move will be easier and safer, but this may not be necessary. Also, depending on where your moving the tank to and from, consider putting some large sliders that you can get at the home store under your cabinet and slide rather than lift and carry.
Re-assemble is straight-forward too...substrate, equipment, hardscape, plants, water, filter on for a bit, replace fish. Remember the water that they've been in may not be water that you want to reuse depending on the time spent.
For adding water, I use a spaghetti strainer, over a plate if you have the room to set a plate. Takes the force out of the stream. Of course, you can't pour the water from your buckets,complete with fish into the strainer. If you don't want to net the fish out of the buckets, save this step for last when you have a lot of water in the tank, pour slowly and carefully and watch your level. You may want to empty much of the water before the pour with your pump if you gonthis route. I wouldn't try pouring water into the sink, or outside to lower the level, fish tend to sneak out. If you dodecide to do that, plug the sink first! I speak from experience.
Good luck. It isn't that hard, just time consuming. It is an opportunity to change or clean. If you are going tonget through the whole process in a day, fauna should all be fine. To reduCe stress, keep buckets away from activity, cold, and bright light.
Have fun. It will be fine and you'll feel good about the extras you accomplish....like after completing a spring cleaning.