Re: 1x8 twist
The rifling twist imparts spin to the bullet in flight (like throwing a spiral football). The longer/heavier the bullet, the faster you need to spin it in order to stabilize it in flight.
While there is some risk of overstablizing light weight/shorter bullets which would degrade accuracy, the bigger problem is when you understabilize the longer/heavier bullets. That problem is compounded when you consider that the these are the high BC bullets preferred for LRH.
When in doubt, build your rifle with a twist sufficient to stabilize the heaviest/longest bullet that you intend to shoot.
Hope this helps,