What are your pravaras? According "vishalamani karmakanda," if you are of Vasishta gotra and of the maadhyandini shaakha (shukla yajurveda) you can follow paaraskara sutra and if you are of the taittariya shaakha (krishna yajurveda) you can follow aashvaalaya sutra.
If you don't know this information already, it means that your parents and ancestors haven't been following this very closely. I would just follow what is most convenient to you.
When you say that you are a krishna yajurvedi, aapasthamba sutra, it should naturally follow that you observe the rules given in aapasthamba sutra. For example, if you recite your "abhivaadaye", you will come to "...pravaraanvita vasishta gotra, aapasthamba sutra, yajussaakhaadhyaayee....sarmaa naamaaham asmibhOH". If you can recite the abhivaadaye without doubt, the sutra is there. Gotra and sutra need not be the same.I belongs to Krishna yajurveda , aapastamba sutra ..
My gothra is Vasista gothra.
I am confused on following the grihya sutra since aapsathamba smrithi and vasista smrithi both are available.
Please advice which smrithi i had to follow.