A well-worn path; lots of good info out there.
Are these Sierra 168HPBTs, or one of the others? Doesn't matter, they'll all do a good job.
Seat your bullet to 2.80" overall length (i.e., magazine length). Don't fuss about crimping your bullet, this is rarely a good thing with match bullets.
Full length size your brass. Monitor it for head separations and other damage, M-14s are rougher on brass than a bolt gun. For now, figure on a case lifetime of 3-6 firings.
Seat any Large Rifle primer. Make sure that every single primer you seat is "below flush". If any primer seats without meaningful resistance, discard that case before you fire it.
IMR-4064 is a very good powder choice. The only "bad" thing to be said about it is that it doesn't meter very well, because its sticks are quite long. This doesn't matter - with the correct load, it does not matter if the powder charge from round to round varies within a 1 grain window.
Other good stick powders are IMR-4895 or H4895. Some good ball powders are H335, WC748 and BL(C)-2. Any of these powders will produce very good results, don't bother spending time trying several of them hoping to get better results with one of them. Choose any one of them, based on price, availability, commonality with other rounds you loads, the throw of a dart or the flip of a coin, etc... any one of these powders will make very, very good ammo for your M-14.
As for charge weights, you say you've made a few rounds already with 42 grains of IMR 4064. Hodgdon's online data indicates a start load of 41.5 grains @2518fps and a max load of 45.9C @ 2766fps. So your initial few rounds of 42 grains is a very good place to start.
Before you test your ammo, clean your rifle's bore and action. Patch the barrel dry, then patch the chamber dry. Then lube it (in particular, a small dab of grease for each bolt lug, and perhaps a small amount of grease or some light oil to the action's rails).
When testing your ammo loaded with 42 grains IMR 4064, check it for accuracy, and for reliability of feeding, chambering, firing and extracting. More likely than not, this ammo will work just find and if you are happy with the results you could stop your load development right here.
If you care to spend some time on load development, you could then try to work up your load to a higher powder charge. Although an M-14 can usually safely fire a load that is "max" in a bolt action rifle, it is usually not desired (in particular it's pretty hard on the brass). You'll usually see worked-up M-14 loads that are one or two grains lighter than what you could safely load to the max in a bolt gun.
So if you do care to do some load development, load up 10 or 15 rounds at 43 grains, and 10 or 15 at 44 grains. Test them, and see if they are better in any way than your 42-grain loads (they might be, but they very well might not be). If your 44 grain load is clearly better than the other two, I might then try 44.5 grains as well. Since the book max load is ~46 grains, I wouldn't bother trying any more than 44.5 grains.
