I did something similar a month or so ago. I held 21 fish in a 40b with a 20g sump. My tank was well established (>1 year, with good live rock). But still, ammonia spiked to almost 0.2 ppm, nitrite to 8, and nitrate to 15(!) [That was crazy - I've never seen an NO3 reading above ~5 except while doing standard curves. ]
I advise you get a bunch of water ready and plan to change water daily...
If you have an algal refugium in the system (all my systems do), you can also crank it up by adding some extra chaeto from another tank and turning the fuge light on 24-7.
FWIW I had good success. 2 of 23 were DOA, so those don't count. 2 more died in the first few days. 19/23 survived and have remained healthy for weeks now after transferring into their homes (14 different tanks).
I didnt do any harsh medications or put them through any salinity stress or anything, just added a bunch of prime soon as I opened the bags, then put them through a ~1-2 hour acclimation as I slowly adjusted salinity (these trans shippers and their low salinity water, /shakes fist vaguely in the direction of the Indo Pacific). [my tank holds corals so adjusting the tank to match the bags was not an option]
So it worked out, but yeah, I had to really babysit them during acclimation and in the 24-48 hours they stayed in the tank. If your tank wasnt mature to start with I do worry about nutrient export. My suggestion would be
a) have lots of water on hand for WC and
b) add live rock and macro to the system if at all possible (e.g. if you have some in another tank that you can spare)
Good luck!