I have not used 6-BA to stimulate seed germination or have done any other in
vivo application, but I have used it in tissue culture of various plant species.
6-BA is a synthetic cytokinin that is normally used to break/reduce apical
dominance in shoot cultures or to stimulate outgrowth of (dormant) buds for
example in node cultures. Further it can induce adventitious shoots, that is
that new shoot meristems are regenerated and can grow on to build normal shoots
with an apex and lateral buds etc.
(BTW, it is often used in combination with an auxin in low concentration)
A side effect of cytokinins is often that they inhibit rooting, more precisely
regeneration of adventitious roots due to a direct effect or due to accumulation
So you might stimulate shoot growth in seeds/seedlings, but
might inhibit normal root growth.
6-BA is of medium strength; for example Kinetin is weaker and Thidiazuron (TDZ)
is much stronger.
It is used in concentrations of less than 0,1 mg/liter to 10,0 mg/liter or more;
for example in Phalenopsis shoot cultures 2,0 mg/liter is often used.
6-BA can be dissolved in 1 n HCl or in 1 n KOH and be diluted with H2O to make a
(stock) solution of 0,5 or 1,0 mg/milliliter.
I heard of in vivo applications of cytokinins, but don't know any details
(concentration, application frequency etc.). But I remember, that unwanted side
effects were noticed, for example inhibition of flowering or malformed habitus
So, one might be careful in regard of concentration and application frequency
Hope this helps in some way,