Which Lee turret press do you have? If you have 4 stations, use the separate crimp die unless you've added a powder check station. In general, most target shooters over the last 50 years have found better accuracy from a separate crimp.
The only counter indication I've found for the Lee Carbide Factory Crimp Die, specifically, has been when bullets were large enough that they were consistently significantly resized by it. This can happen when brass is extra thick or the case bullet is extra wide. You have to check it for yourself.
Guns are individual about leading, but you can generalize that lead bullets are pickier about the gun and bore condition. If you get a cast bullet matched to a gun whose bore is smooth and without constrictions, you get only traces of leading and it seems to self-limit, rubbing out of the bore as fast as it forms. My .45 Auto barrels are all like that. They are pretty smooth on the surface and I'll pick up a little lead in the corners of the first inch of rifling. But I've shot one of them up to about 3,000 rounds without cleaning, to test feed duration, and the amount of lead was really no greater at the end than it had been after the first twenty rounds. Not much.
One thing that helps reduce leading in self-loading pistols is headspacing lead bullets on the bullet rather than the case mouth. It also improves accuracy, often significantly. The limitation is that your gun has to be able to feed the greater length. You just have to try it to see (third from left in illustration at the bottom).
Revolvers are the most picky. For one thing, it is common for them to have a constriction of several ten-thousandths where the barrel screws into the frame. I've heard of instances of this being as bad as three thousandths. Such a constriction can spoil lead bullet accuracy and requires lapping to remove. For the amateur, firelapping is best for this.
For another thing, the chamber throats in revolvers are often not quite exactly the same size. They need to be the same size and at least half a thousandth bigger than the groove diameter of the bore, and the bullets need to be sized to fit that throat diameter for best accuracy. I like revolver throats closer to 0.002" over groove diameter and cast bullets that same size.
Still another thing is that barrel cylinder gap be uniform in all directions. An uneven gap will tend to gas cut bullet bases slightly unevenly, which adversely affects accuracy.
Finally, you want the timing of the cylinder chambers to line up with the bore when they lock into position. If yours don't line up well, see a gunsmith. You may want him to uniform the chambers by reaming them anyway.
A pause for the COZ,
Try skipping lubing in the Star and just use Lee Liquid Alox (or White Label Xlox lube). It seems to work well even on bullets without the little tumble lube micro bands, especially at handgun pressures and velocities. If the bullets fit the gun, try skipping sizing, too. I find that bullets I can shoot unsized are typically most accurate and lead least.