I agree detailed breakdown between buffalo and NYC will be very challenging.how are you planning to provide detailed break down? it might be very hard for you tell them when you would need to go to NY isn't it? like your plans could keep changing based on your meetings in NY etc right. it is not just about giving the plan, but you need to stick to it while traveling as it will be tied in your petition.
in my opinion, you can avoid buffalo LCA altogether and travel to NYC as and when required.. like once or twice a month and work remotely from Fort Eerie rest of the time. that is what most people seem to do these days.
alternatively just give Buffalo alone as your location in LCA and just go to NYC whenever required for meetings.. you are allowed to go to different office not mentioned in LCA if it is just for short trips for meetings etc. keep the destination mentioned to CBP consistent to Buffalo all the time.
Regarding avoiding Buffalo LCA altogether, this option i never thought of. Does travelling only once/twice a month on H1B raises any suspicion at the land crossing? Are people doing this? Does substantial presence test mandatory for H1Bs?