Hello
I've done this in the past, and here's what works for me: Wrap a wet towel around the fish (It will become wet once submerged, naturally) and lift/lower the fish into a large plastic trash bag, tripled up, within a styro box or appropriately sized plastic container with water in it. Keeping the fish wrapped, but in the water, will help reduce (or stop) splashing. Cover, and transport, then lift the towel/fish into the new tank and release.
This is the ONLY method that will work effectively with such large fish with a MINIMAL amount of thrashing around and water scattering. I do this with my large lungfishes, and used to do the same with my large Cichlids when I had them.
In my personal opinion, a net can do a lot of damage to fins and scales because the fish can and will still thrash around within, and you don't really want to be squeezing the net too hard - you could end up injuring the fish as well. Then there is the doubled risk of releasing the fish from the net into the box, then netting again, then releasing again. Needless to say, most people don't even have nets that are large enough, either.
A towel also helps calm the fish due to the eyes being covered up as well.
Hope this helps.