What dies do you guys recommend? All brass will be from my pistols not range brass. Will be setting up my old Lee Turret press. What steps are necessary for the 357 sig? Will not be reloading large numbers in either caliber.

In my experience you either need to pony up for the Dillon carbide 357sig die set, or else size with both a 40s&w die and then the 357sig die.

I opted for the latter as I already had 40s&w dies. Just gotta handle the brass twice as much.
As I don't shoot much 357sig, I don't mind.

I spent the extra bucks on the Dillon dies and for good reason. I'm loading on a XL 650. I started off with both Lee and RCBS 357 Sig dies and had issues with case neck tension and some other inconsistencies. I was not willing to experiment and chalked it up to die differences

The Dillon have been flawless.

I load my 357 sig like C-Dubs. Size with .40 first, then the .357. My .40 dies are Lee, and the .357 dies are RCBS. I load cast 135 grain powder coated bullets, sized at .358, and have no problem with neck tension.

I use a Redding "de-bulge" 40S&W die on both cartridges as never know what could accidentally show up in my brass. This is particularly important if the brass came from a less supported barrel (Glock). Maybe you won't have that issue but it's cheap insurance for problem free feeding.
I then run the 357 SIG through a Hornady 40S&W carbide sizing die and set aside in marked containers.

Other than that everything goes through the progressive press as usual through Hornady dies. I had used Lee dies in the past and they were fine too.

As mentioned, I'd stay away from the RCBS 357 SIG dies. I had all sorts of feeding problems with them, and tried some Lee dies as a last resort and they worked fine. Something about RCBS sizing off the mouth vs. eveyone else sizing shoulder or something like that. Also use as little bell on the mouth as possible on the 357 SIG. Bullet set back is a risk with the round.

dillion carbide dies thru my 650, bullets and bullet seating depth matter there are many threads on this just do a search.

Any dies but the RCBS for 357sig, they never got it right. I prefer Dillon, only carbide ones, but if not loading on a progressive, you would need an expander/flare die.

I do both on a Lee turret with Lee dies just stay away from speers brass its a pain to decap it has a small flash hole . It broke the decaping pin sanded down new pin but now just toss speers 357 sig brass.

What Fred said.

I use Dillon carbide dies on my 550b.

Dillon dies on my 650. I'll use RCBS dies on a Rock Chucker to make maybe 20 or so rounds for testing. I've read so much about bullet setback in a 357 SIG, that I was almost afraid to bell the case mouth. I do it very slightly. I had some bad primers last week and had to pull them with my kinetic bullet puller and it took some effort to get them out.

Received my Lee dies and dug out my old Lee turret. Loaded one round of 357. Resized with 40 die then 357 die. Belled case just enough to start bullet. Seated to a depth of 1.125. Crimped slightly. Cannot push bullet back in case with lots of pressure. Loaded round chambers same as a factory round. Now need to check how round cycles slide.

Sounds like you’ve got everything going correctly.

What bullet and powder did you settle on?

115 gr with the longer straight sides from RMR and HS6 to start with.