I honestly think this is the worst use case for a 3d printer. The part isn’t improved by printing. You can buy the part easily. The cost of modelling time and printing is more than the replacement. There’s a decent chance the replacement part would have arrived quicker than the print took… Sorry to be a bore, it’s better than an octopus or another benchy, I’ll give you that.
What’s the speed of the road? I would personally join the road earlier so that I can manoeuvre across with the traffic, but if the road is super fast I’d probably pick A. That is unless right on red is permitted, then I’m not sure.