The first handgun we purchased for me is the Ruger SP101. I am not comfortable with it because of the grips - I have long fingers and the grip on this revolver just doesn't feel comfortable to me. My current handgun is a Kimber Ultra Carry in .45. Down side is I have trouble with the slide so we are looking at alternatives. I have my lifetime LTCH.
WRT the SP101, there are several aftermarket grips available that might make it much more comfortable for you.
A compact .45 will have a very stiff spring. Try both the overhand method or the slingshot method of racking the slide to see which works best for you.
Make sure to get as much surface area of your hand and fingers on the slide as possible - without blocking the ejection port - this reduces the pressure on your fingers and makes racking the slide a bit easier. With either method try to get the ball of your thumb involved which will give you more grip strength too.
As mentioned keep your elbows tucked in to your sides to help get your shoulder muscles involved.
