Sorry for not chiming in earlier, by a 1.2 molar XS Sister meant to multiply your tryptamine by a factor of 1.2

So if you have 1 mole of NMT  or 174g

you would need 1.2 mole of acetyl salicylic acid or 216g

Mind you, a larger XS of aspirin will not cause any problems with this reaction. Also when calculating the weight of your aspirin, use only the active ingredient weight/dose/tablet, not the weight of the entire tablet, fillers and all.