thank you very much for preparing this draft. An update of the SM input 
parameters is mandatory. Here are my comments to the draft:

1.) In Section 2 there should be comments about the proper implementation 
of the complex-mass scheme, i.e. the evaluation of the 'real' input 
parameters from the PDG values.

2.) Concerning the quark masses you should also comment on the 
correlations between alpha_s and the mass values that has to be taken into 
account for a sophisticated analysis of the parametric uncertainties.

3.) The error of the charm quark mass in Eq. (12) is too small, i.e. 
non-conservative. It should be multiplied by a factor of two analogous to 
the alpha_s error.

4.) I think that it will be very problematic in the context of elw. 
corrections to use a 4-loop relation between the MSbar and the pole mass 
of the bottom mass if the calculation of Hbb production is only known at 
NLO in the 4FS. Elw. corrections will be very sensitive to the relation 
between the bottom mass used in the kinematics and the value of the bottom 
Yukawa coupling. This is the reason why I am always emphasizing to use the 
relation according to the order of the calculation. However, if there are 
definite arguments against this strong consistency I am open for learning 
about them. I think that the embedding of running masses in the full elw. 
corrections is still a subject for further studies due to the elw. 
symmetry relations to be fulfilled.

5.) The uncertainty induced by the m_b dependence of the PDFs should *not* 
be obtained by keeping the m_b value of the partonic cxn fixed at the 
central input. This is inconsistent since there are too many correlations 
between hadronic bottom observables introduced in the global PDF fits and 
the chosen b mass value. An independent variation may easily lead to an 
overestimate of the corresponding uncertainty.