From factory to hand loads

[WV1951]

Full of questions today.
Been using only shelf ammo for my .223 12FV and so far the 68-69 grainers have shot the most consistent. My SIL has offered do do some reloading, so I am going to be at Cabelas tomorrow to maybe bite the bullet(no pun intended).

Should I stay with the heavies or could I have good results with lighter pills with a proper load work up?

I don't want to burden him with a bunch of trials, but I'll pick up a variety if it would be worth it.
What have you found going from factory to hand loads? I know some barrels like heavies and some like the lighter stuff. Is factory ammo any indication or meaningless?
For the most part, my powder choices will be determined by pill size. Right now(for heavies), it looks like H4895, IMR 8208 XBR, and maybe 1200 MR or Benchmark(Cabelas doesn't have RE15 in 1 pounders). I already picked a box of Sierra MK 69gr. HPBT.
I'll get either CCI 400 or Rem. 7 1/2BR(if in stock) primers.