I prefer NOS. That is what I used, but they are hard to come by these days and the price for them is 'out there'. Look at Rick's and see what they have. I bought a lot of panels from them. They offered US Made panels and they were always very nice pieces with the correct gauge thickness.
I'm in the mini tub process right now and they are not as easy as DSE made them out to be. I started out going to just split the stock inners and then decided to just use the DSE deep tubs. The main difficulty I have found with their directions is they give you no reference points for their templates. However, I haven't used their templates other than for my own reference. There really isn't any real clear cut way of doing the tubs, so DSE has made it as painless as they possibly could I suppose. It's not a painless operation though. It just takes time and a little tweaking here and there. Don't try to cut it out all at once. Make your cut lines and then creap up to them fitting the new tub in during the whole process. That way you'll get a perfect fit for the end result. I have already cut my frame rail out a little too much and am going to have to go back and weld a little bit of metal back in to make up the gap. I hope I can have these done by next weekend.
What do your quarters look like at the rear window channel and rear trunk/window filler panel? Mine were rotten there necessitating me to have to replace both quarters. I sure wish I had mini tubbed the car then instead of doing it now