Chanukkah

Question

I noticed you state in the Halacha section of the website that one should light chanukka candles after shabbat candles but before sunset. I know that this is one of the opinions cited in the Rishonim, but it is not the one brought down in Shulchan Aruch and poskim. In fact, ashkenazim have the minhag, also held as halacha by some rishonim, to accept Shabbat once candles are lit. What is the reason for your pesak? Secondly, you said a person who is travelling should not rely on the lighting at home. But according to the gemara and rishonim, if his wife is lighting at home he is yotze, and to light again would involve a beracha levatala or, at best, a beracha she-eina tzericha. I would like to better understand the Rav's position on this matter as well. Thank you as always