A. For Morning+Early daytime: Instead of Gloop can I simply cook oatflakes / oatmeal and add into this mix of small sliced vegies (carrot, cucumber), then from this prepare daily small portions and put them in the fridge. --- How many grams of these I can give him each morning?
No. You can't just feed it oatmeal and nothing else. It needs different types of whole grains mixed with different veggies (cucumbers have no nutrition, you can offer them as the 'veggie of the day' every now and then because all birds like cucumbers but not often - for gloop, you need to round up the nutrition and that's why you need a range of yellow, orange and green veggies). And no, you cannot keep in fridge. If you make a large amount of gloop, you need to freeze the daily portions to retain high nutrition. Let me explain: you cook the whole grains 'al dente' so they are softer in the outside as they become imbued with water but remain a bit hard in the inside (birds like them better this way). You let them cool completely. Then you add frozen veggies without thawing them. You mix. You split into daily portion and freeze them. Every night, you take out a daily portion and allow it to thaw.
A.1. Instead of boiled hard egg which I put vitamines on, I will use boiled white rice chunk with vitamnes spread/poweder on it.
I don't like this method because you can't tell how much of the vitamin powder is actually ending up inside the bird and you do NOT want to overdo it with the vit A or the vit D3 (because the excesses of both end up in the liver in the form of fatty nodules and too much vit A causes cancer).
B. For noon time, put him, few solid slices big of fruit or/and vegie.
No. Birds eat two big meals: breakfast and dinner. He needs his fruits and veggies early in the morning BEFORE his gloop.
C. spray of millet, can you clarify how it looks? can't I just give him millet seeds?
This is what a millet spray looks like: https://animals.mom.me/what-is-a-millet ... 49156.html and they sell them in all the bird stores but, if you can't find them, you can use the regular millet.
D. Optional: Oatmeal I can make time to time, Dr' Quaker works?
D.1. Dust Time: Give him soft warm boiled rice or oatmeal made of oatflakes with Budgies mix.
You can give it oatmeal but not as 'the' food. It can be an extra. And it cannot be the instant kind but the old-fashioned one.
And no, do not mix cooked rice or oatmeal with seeds. It will only make a mess of things and, besides, you feed the seeds at a different time than the cooked grains, rice or oatmeal.
E. Would appreciate your answer about my question in my above response, related to anti biotics, how many days will be giving this to him?
Give it 4 or 5 days of probiotics.