lpSolve API - add Vs set

Hi,

Using the package lpSolve API, I need to build a 2000*100000 constraint matrix.
I wonder which method is faster:

(a) 
model = make.lp(0,0)
add.constraint(model,	...)

or

(b)
model = make.lp(2000,100000)
set.constraint(model,...)

Thanks
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KC