What herb has the smoothest smoke? I want to sandwich the dmt. I dont want to use marijuana.

Try experimenting with caapi leaves, or mullein, with small amounts of white sage or lavender. Have you considered making changa?

i use the dried mint leaves from the grocery store

as sold they are so dry they will go up like gasoline
add 1 tablespoon mint leaves to a shallow dish with 7 drops of water cover with plastic wrap microwave 30 sec
the mint leaves will come out with a perfect tobacco like moisture content

I have found Jasmine flower to be delicious and easy on the lungs. Caapi leaf is nice, and adds its own quality to the 'high' - Damiana is also very nice, but a little harsher. You could always try combinations - my latest Changa blend is: Jasmine flower, Spearmint, Lavender, Sage, Blue Lotus & Daminana with red caapi alks in a kind of salad. It is nice to look at, and even nicer to smoalk! Just experiment, that's part of the fun, most things that can be made into teas seem to be a good starting point such as Mint, Lotus flower or Jasmine.

My first enhanced leaf was Peppermint Tea, and that was a lovely smoke...

Is changa just the dmt dried onto leaf to make dmt infused leaf?

Yes, all you would do is get a small jar or something, put all the crushed herbs and DMT in there @ a 1:1 ratio, 1 gram of DMT to 1 gram of herbs total, and then add a solvent like ethanol, or ISO, or acetone, or even naptha, evaporate, stir / chop up, and you are good to go. I would recommend using .5g caapi leaf 250mg mullein 100mg salvia apiana 150mg lavender or something like that for every gram of DMT you use.

I like to use blue lotus. It's not necessarily the best tasting smoke/vapor on the planet, but it's very easy on the lungs, and it can potentially add a more refined character of quality to the experience.

Use mullein it works

In my experience...

Mullein will clear out your lungs a bit, which is nice. It makes your nasal passages feel fresh and clean.
Scullcap can relieve the anxiety a bit, especially if you smoke some right before your trip. Smoke too much and you'll feel like your walking on air.
Blue Lotus gives kind of a subtle euphoria.
Caapi Leaves are good to use anyway.

I ordered Mullen and will first try to do the sandwich method first then the dmt infused mullen

It's only considered Changa if you have either Caapi leaf or added Harmalas for extra MAOI potentiation. Well worth going to the extra effort of extracting some vine IMHO...

I dont need to be on the diet to smoke maoi right?

No, I have smoalked Changa after eating blue cheese, had a beer or two, or had a caffeinated beverage, doesn't seem to have any negative consequences like oral may throw up IME