My son has been on Zantac since he was 8 weeks old, always the same dosage of 1mL twice a day.  In the past few weeks, he has started gagging/even vomiting Stage 2 vegetables and rice cereal, all of which were not a problem as Stage 1 food (cereal was never a problem)...although I did note that carrots, sweet potatoes and maybe squash caused more small spit-ups.  The recent gagging/vomiting (even of a full 6 oz bottle this past weekend) caused us to contact the pediatrician who has now switched him to Prevacid 1/2 of a 15 mg solutab dissolved in water in the morning.  (I am still not sure why he didn't first try a higher dosage of Zantac?) 

1.) The past 3 days of Prevacid have shown no improvement at all, maybe even worse, as last night he woke up every other hour and could not get comfortable even sleeping on my chest in the recliner.  Lots of wet burps, the congested sound coming from his throat, yellow saliva with his spitups when all he had was formula or green food that day.  I was told that the Prevacid could take up to 2-4 weeks to show results.  Is this true?  Would it be harmful to continue to give him the Zantac, maybe just in the evening which is definitely the worse time for him?  It seems that it would help him, to at least neutralize acid that is still not being effectively blocked.  Could he be on the wrong dosage?  He weighs about 17lbs.  I have seen posts indicating babies on Prevacid 2 times a day or a full 15mg.

I do believe that he is teeth on his 3rd tooth as well which isn't helping the situation. 

2.) As far as solids, I am now lost on how to progress him.  Per his pediatrician, at 4 months he was introduced to rice cereal mid-morning and dinner; then progressed to Stage 1 vegetables at lunch as well as + cereal at dinner, then we were attempting to progress to Stage 1 fruit recently by having cereal + fruit at breakfast, Stage 2 vegetable + fruit at lunch, and vegetable + cereal at dinner).  At his 6 month apointment 3 weeks ago, the pediatrician had recommended Stage 2 meats which is when I really noticed the gagging to start to increase, and at meals, where previously there had not been a problem (we were thinkig he was gagging during the day as he always had his hands in his mouth).  I stopped trying the meats, and started introducing fruits instead (I had been avoiding them as they seemed acidic to me, but pears he liked/no problems, however bananas also caused immediate gagging, applesauce alot of spitup through the day).  Since he was so fussy/crying/gagging in the past weeks I got concerned with him developing food aversion or worse choking.   This week I have regressed, just giving him cereal in the AM/PM, and stage 2 peas or green beans (since these caused the least spitup in the past) watered down at lunchtime.  It is slow going and a struggle and when he starts to actually cry I do stop, but I am thinking that just feeding him a bottle would be a bad idea, I don't want him to lose his solid food progression plus I know he needs the "bulk" to stay satiated.  This has been somewhat successful, as he wouldn't take any cereal last week; but in the past 2 days I am now back up to 2T of the rice cereal at AM and PM (adding alot of water to make it runny) and a full 3.5 oz of veggies at lunch.  Are there any real recommendations for solid foods to avoid or how to progress an infant with reflux?

Sorry for all of the questions but I am at my wits end...relying on instinct alot but I don't want to harm him either with over-medicating him or giving him the wrong foods