Hard lead bullets won't harm or excessively foul your pistol...if you don't try to make speed demons out of them. Bullet heels melt when there's too much powder and pressure. If you want "hot" loads, use jacketed bullets when you build them.
The very best recipes will be found in reloading manuals. Generally, it is not a good idea to uncritically use someone else's load, if only because of liability issues.
Buy a good manual, and slavishly follow its complete recipe, including even the brand of primer (if it's specified).
Later, after gaining some experience, you can begin tweaking recipes...when you know what danger signs to look for, and what to do about them.
The best thing to do is to find one really good combination of ingredients that delivers reasonable accuracy and reasonable power, and then to stop experimenting.
I've been comfortably and successfully using the same load in my pistols for the past 35 years. I see no reason to change.