PPI Analysis

Dear AFNI users,

I am planning to run a PPI analysis and I was looking at Gang’s pipeline beforehand.

My main doubt is about the Reconvolve phase, where the waver command is used. Specifically:

waver -GAM -peak 1 -${TR} ${sub_TR} -input Inter_neu${cond}${cc}${sd}.1D -numout ${n_tp} > Inter_hrf${cond}${cc}${sd}.1D

My question is about the input for TR (or dt or sub_TR). My TR=0.901s and my stimulus=10s. What should I use then in the above command?
I have seen an example posted by a user in the past with the following values: TR=1.5s, stimulus=7.1s. In that case it was ok to upsample 15times by using sub_TR=0.1. What does that value comes out? Why not use 0.2 for instance?