1400 might be a struggle. If you have the money gun, DT 240 centrelock and CX Rays would get you to around 1450g on a good day. Fairly sure there are some Stans rims lighter than those that could get you nearer 1400?
If youre not absolutely set on that weight, 1600g wheelsets can be built up much cheaper. My bitex centrelock on wtb i21 was only ~£220 all in for 1700ish grams. Cx rays would have got me sub 1600 i think
1400 might be a struggle. If you have the money gun, DT 240 centrelock and CX Rays would get you to around 1450g on a good day. Fairly sure there are some Stans rims lighter than those that could get you nearer 1400?