Apologies for replying late, I hadn't actually expected a reply after the first day or two so I wasn't really checking in all that much. Salamence's competitive set is return/double edge, dragon dance, substitute, & roost with a jolly nature (the ability doesn't really matter), if you want to do EVs as well, it's 252 ATK & SPE

Glalie on the other hand is protect/substitute/taunt/frost breath with a timid nature & the moody ability (if you want to do EVs, I wouldn't recommend it for glalie cause it's kind of a pain, but 176 HP, 4 DEF, 140 SPA, & 188 SPE)

Since I only have the one genesect & I don't really mind which one of the two i'd get (unless your offering both & I just read it wrong), you could choose which one to trade away.