According to Hornady they recommend a 1-8.5 twist for their 147 eld.
Using Bergers twist calculator, at 1-8.5 twist you need at least 2800fps. Anything under puts you in marginal stability. A 1-8 twist is comfortably stable, even at a velocity as low as 2600 fps.
I shoot the 147s out to 1000 yards regularly with my 260 @ 2800 fps and have not noticed any inconsistencies.
The Sierra 150 smk is a good bit longer than the 147 eld (1.435 vs 1.5 in). Sierra does recommend a 1-7.5 twist.
Plugging the Sierra data into Bergers tool, looks like a 1-8 @ 2700fps or fast is enough to stabilize the 150 smk, but its right on the edge, so yea.. with those 150 smk you'd want something faster than 1-8.
In regards to consistency, I've read anecdotes over on accurateshooter.com that at distance the hornady elds are not as consistent as the bergers. One example was a guy in the UK who shot F Class using bergers one year and then switched to ELDs the following year. The year he shot hornadys he supposedly had a significant drop in the leader boards.
I don't compete nor do I keep paper scores of anything beyond 300 yards so I can't comment on the validity of this idea that hornady's are less consistent compared to some of the more popular competition bullets. I can say, that at 1000 yards with my 260s, the humble hornady 140gr bthp shot as good or better (as in consistent hits on target) as 140 & 147 elds, 140 rdf, and berger 140gr hybrids.