Nice Hopefully everything turns out okay. I have some Merlot,Alicante Bouschet, and i tried planting some barbera which didnt do well and died. So i just planted some Cabernet Franc the other day to replace them.
Regarding fungicides and insecticides in your original question; the answer probably lies in the specific vulnerabilities of your varieties and the micro climate you have in Texas. I suspect your not getting answers because many are not familiar with your varieties and unique problems associated with Texas climate zones.
As Masbustelo said, start buy figuring out which fungal diseases you have to deal with. You can think about fungicides once you know that. Here are some things to keep in mind once you reach that point
Every fungicide has a pre-harvest interval (PHI). You will need to know when to stop one fungicide and replace with another
Each fungicide has a mode of action, which is denoted by its FRAC group. Examples include strobilurin fungicides like Abound and sterol-inhibiting fungicdes like Rally. If you need to spray for fungal diseases, you will want to develop a spray schedule that uses fungicides with different modes of action. It is easy to accidentally buy two different brand name fungicides that have the same mode of action.
Some diseases, like powdery mildew, can develop resistance if you overuse any one type of fungicide. Know and understand how many times you can apply a given fungicide in a row and how many times you can apply it over the growing season.
For insecticides, I only spray once or twice a year when I observe a problem (typically Japanese beetles)
Also for preventative sprays there are a number of potassium bicarbonate (baking soda) organic sprays on the market. They work by changing the pH. If you arent seeing problems you can use these as often as you want. Take a look at Serenade, Green Cure, and companion. Last year I used Mancozeb and sulfur until July 1st, and then switched to the organics. I am a home grower and plan to do the same this year. I have different varieties than you and I'm sure different climate as well.