I use this recipe...
3 c crisco
4 # pwd sugar
2 tsp creme bouquet
1 tsp butter flavor
1 tsp vanilla flavor
2 tblsp cornstarch
2 tbslp meringue pwder
1 cup water
salt

I creme the crisco then add the pwd sugar /dry stuff alternating with the water I.
I am just not sure anymore how long to mix it for and at what speed on my KA mixer.
What does everyone else do?

I've only really used the wilton recipe.

1 cup crisco
1 lb powdered sugar
1 TBSP Meringue Powder
1.5 tsp vanilla
0.5 tsp butter flavoring
0.5 tsp almond extract
2-3 TBSP water

I blend the crisco, vanilla, butter flavor, almond extract and water. Then add the meringue powder and sugar. usually, I make a double batch. I have a psuedo KA mixer.

You'll know when to stop.
As soon as you put the dry ingredients it is going to get kinda lumpy and then it will come together, then you'll know it is time to stop. Do not overmix because you don't want to have a lot of air bubbles in your icing.
I can't tell you exactly how much time, but it is not more than a couple of minutes.

I always use the paddle attachment with my KA. It seems to get less air in the frosting.

I know in the past my old instructor said to mix it on high for 7 min but it does get a lot of air in it. I have been doing it on 2 or 3 for about 10 min or less. I just don't want that gritty taste ..

I creme my shortening with my flavoring for 15 minutes on high(KA). I helps cut down on the greasy taste. Then I alternate in everything else slowly with the mixer on low. And only mix until incorporated. No problems at all with air bubbles.

After everything is in the mixer mix on a low speed. You want to mix until everything in incorporated then just a few minutes more.

The faster you beat it and the longer you beat it the more air bubbles you will likely get.

15 min seems like a long time to mix it to me anyway. I mix the shortning and such for as much as 5 min if it's still cold (straight from the fridge) but after the sugar is added, it's usually only a few minutes until I have the consistency I'm looking for. the only thing I mix for an extended period is royal icing.

Yes that is what everyone says SheilaF. But if I cream those any less then my buttercream taste like crisco. Yuck. I only mix it with the flavoring and it helps my buttercream to be smooth. Then when I add the sugar and water I only mix to incorporate.