Weaning

Over the past 10 days I have started introducing foods to my 6mo. All vegetables to start with. I want to now start offering porridge in the morning and then continue with exploring the veg etc midday. I currently exclusively breastfeed I have 2 questions. 1- do I buy the baby specific porridge from, for example, cow & gate. Or do I use the same rolled oats we have in the house for my 2yo, but blend them so it's finer. Is there a health benefit for baby to have the baby specific one. 2- as I exclusively breastfeed, I don't pump very often or feel like I produce enough milk to pump, and use that in the porridge. So, do I just add water, try and pump enough to put that in the porridge or do I add formula milk to it do she's getting additional nutrients that water doesn't offer. Thanks in advance!!