Got my 2 full frame rails off Ebay from Tamaraz. Had no fitment issues that I didn't consider normal. No regrets.

However I did NOT do full floor replacements like you are planning, I did piecemeal of smaller floor parts and patch panels, and I kept as much of my original sheetmetal as I could. I've always found that smaller parts are MUCH easier to "massage" into place when needed...so that may have masked any major frame rail fitment issues. Whether those rails will match up with whatever floors you bought I have no idea. So it might be wise for you to stick with the same mfr as your floors.

Frankly I doubt you have very many choices in manufacturers...and I don't have any idea who made the Tamaraz rails. I'll suspect there are a lot of sellers all selling the same parts.