25g in my opinion is too small for glutes for oil based.
I just got a bag of them in, what a pita to draw, and I am sure it will be fun trying to push the plunger in. I should have used what I did before and go with a 23X1.5.
If you are going to draw water based go with a 25gauge by 1 inch for delts, hammies, or tri.
25 x 1.5 for glutes on water based.
Oil based go with 23x1.5 on glutes, or 23 x 1 for delts, hammies, or tri's.
Yes, the needle is bigger. If you inject correctly pain will not be an issue. Scar tissue wil start to form if you do not rotate injection sites.