Equivalent to DL Gold is roughly UA Gold (although UA Gold has more benefits, it has the same requirements as DL Gold) and LH SEN. SEN is much more difficult to obtain than any of the others, as it is basically a 100k tier status. If you can't manage SEN on LH (doubtful if you are only Gold on DL), then I don't think using M&M is a great idea - it is fairly strongly positioned to reward high-margin fliers at the expensive of low-margin ones.
UA Gold gets you Star Alliance Gold, which gives you limited benefits on LH which are probably superior to LH FTL (the lower LH status) for a similar number of miles. However, the only status that will get you meaningful "seat upgrades" on LH metal will be LH SEN (free seat assignments, free exit rows and bulkheads) - if you instead fly UA metal you can get Economy Plus for free at booking as a Gold.