I so wish I could help with more authority but my experience is with 338-26 Nosler. I have 5gn more capacity so take everything I share with 5 grains of salt
I "created" the 338-26 Nosler in 2015, the 33 Nosler was released in 2017. Nothing big, I was just not willing to wait and my 338 WinMag wasn't cutting it. I could rechamber the 338 WinMag.
Always use caution with anything suggested outside of book recommendation. Since I don't think I will be outside book...
I will echo that RL-19 and 7828ssc work in a predictable fashion. I did some work with RL-17used that in my hunting load. 7977 was too new back then. I finished my rifle, worked up my load, completed my 2015 hunt before 7977 had shipped.
A thing to look at is bullet length of the comparable bullet in copper jacket to the Barnes. The copper jacketed will be shorter. The above reference shows a BT and a Spitzer in 225. Compare them to the Barnes TTSX 225 length. If you seat the Barnes to the same COAL as say the Nosler Accubond BT, you will lose effective capacity. If you seat the Barnes to the same depth (amount of bullet in the case) then the amount of capacity is the same and the amount of powder to use should be the same. Clear as mud?
The standard mantra, start low is valid here. If you lose case capacity because of the longer Barnes bullet, look at reducing the "low" to match.
The cartridge is predictable. I started with the load data for the 338 RUM and scaled it directly for lower case capacity and accounting for bullet seating depth. There's an app for that
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I did use a pressure transducer.
Last note: I chose to throw TTSX 185s over RL-17 in the high 3200s range. It was great on elk. My COAL was 3.4 with a seating depth in the case of .413. This was to make my max box length and smooth seating.