Twenty real dimensions beams from the glued laminated timber were tested in our previously works. Twenty advanced FE models were created precisely according to tested beams. Input files for FE models are lengths of segments and local moduli of elasticity. The segment is part of lamella between two finger joints. Each local modulus of elasticity was obtained via non-destructive penetration test. The output for comparison between real beam and FE model is displacement in half span. The quality of input data file from experiments is very important for the good agreement between real tested beams and FE models. In advanced FE models is described distribution of local moduli of elasticity via distribution function. The solution is based on the LHS. Accuracy of each distribution function is dependent on the number of measured local moduli of elasticity. In presented work was used probabilistic approach for determination of corresponding number of penetration tests as function of segments lengths. Results of this analysis will be used in the latter series of bending tests of new real dimensions beams and corresponding advanced FE models.