You can check out smokerbuildermfg.com or call the phone number at smokerplans.net and they actually build a hybrid RF/tuning plate standard offset pit. I'm not sure if they sale the plans for them but I'm positive that they build them. They have videos on facebook, instagram and tik tok, if you're on any of those sites you can check them out. They have a page for smokerbuilder.com and I believe smokerbuilder.mfg on those sites.
He uses tuning plates on this one so the throat doesn't have a baffle, it's just an opening. I'm sure that you could install a solid plate for RF that can be removed and build a baffle that directs the heat straight up if you wanted to go that route.