Hi DG, my ds has reflux and gets Zantac as well, and the 4 month age was very tough with sleeping.

Who knows why but he had a terrible flare up around then. Not long after we got a wedge for him to sleep on, and that made a huge difference. I would definitely suggest trying that or elevating one end of the mattress. It might not help, but if it does it's a beautiful thing.

Solids did help further too, although you do have to be more careful with acidic foods like tomatoes, pears, etc. You might want to talk with your doc about starting him a little earlier than 6 mo. I wouldn't do it without a consult though.
I know what you mean about the running away and light at the end of the tunnel. Don't feel badly for thinking that way, it's really hard to have a reflux lo. Mine is spirited as well so let me tell you that's a deadly combo. Do what you need to do to get him sleeping better, then you can sleep better and be more present KWIM?