Look at the bottom of this page, and click on the PIHKAL link. Then look up N,N, dimethyl MDA. The reports on it say that if it has any activity at all, then it's a very bad experience. There's no entry for the diethyl analogue, but I'd doubt it's much better. So don't waste your time with these synths, they won't be worth it.
If you can get formic acid, then why not make some ammonium formate with some ammonium hydroxide solution, and use that?