You don't influence by pulling the seniority card, you do it with data. If there isn't data to back up your suggested approach being better, it might not be, and you get to learn something new!
Sourcing data is expensive. I think it's best not to underestimate just how much development has to be done based upon gut feel, trust or experience simply because proving it would take too long.
If it's two people arguing their own opinions at each other and neither one has relevant data where exactly do you go from there? The one with 2 years experience or the one with 15?
Sometimes the data is the experience, and it's hard to dump your personal experience on someone and make them ingest it. Sometimes you've tried approach X a couple of times and it always failed, but you don't have a scientific proof it will fail again. You just know from experience if you do X it usually ends up in tears and all-nighters and missed deadlines. Not because you have an Excel table proving it, but because you've lived it.
