We started weaning around 3mo2wks. Max is also on Gaviscon and omeprazole and was recently diagnosed with GORD. He did start to lose weight at one point as his milk intake was less than 15oz in a 24hr period so early weaning helped us a lot!
The early weaning will only help with the vomiting as opposed to the acid reflux, and certainly the foods you give to the baby can aggravate the acid reflux so there are a few things to consider.
I started giving Max just a few spoons of plain porridge after 3 of his feeds every day. The vomiting got better almost immediately. The projectile vomiting stopped and he just spit up occasionally instead of the ridiculous amounts before. I make the porridge with his milk so it's nutrional for him, and make it thick, so it does stay down.
He seems to be constantly hungry at the moment so i've upped his food feeds as he can't tolerate a bigger milk feed than 4oz. He now has the flavoured porridges 3 times a day, in a larger portion, and half a jar of food thickened with porridge. He loves his porridges and gets excited when he sees the spoon so I definitely don't think the food irritates him, as he still has quite a bad aversion to the bottle now.
The porridges worked for a good 3 weeks for us and it's only now we've put him onto different flavours, he seems to be doing well with the jars and likes the flavours but I steer clear from anything that might be acidic, like apples, pears and berries. I also find the consistency of the jars too runny, so have to thicken them, otherwise he does just throw them up and it's a lot messier than the milk!
The key is definitely just trying things slowly, I stayed away from baby rice as it did nothing for Max and found the porridges a good place to start. I was very wary of early weaning and didn't want to bombard him too soon but I have to admit that it's made everyone's life better in this household!