Hi Rarefish...I have 3 chainsaw mills (running 30, 42 & 65" bars on 3120 & 880 powerheads) and been slabbing timber for a few years now...and played around with a LOT of different settings,chains etc...evolving a design through 4 evolutions with a friend and myself, helped a LOT with a rope winch system which makes it easy to operate single handed and easy enough for my wife to be able to setup and use (just to show it IS easy, she's just 5'3"). Anyway!
The only difference between milling chain and std is the angle of the cutters (unless you're talking about skip tooth, which you only need cross cutting/bucking with bars longer than 30" to clear the chip between cutters)...angle to teeth is mainly to minimise chain chatter in the cut and the side drag that creates, causing cutting with the side of the cutter and peeling the side out of the cut on the return along the top of the bar...it leaves prominent cutter ridges...literature says to use 10deg...our experience has lead us to settle on 15 deg which cuts a little faster in the soft woods without chatter...15deg on the top plate and 35-40 deg angle on the edge...depending on the wood...harder - less angle both settings...so just a tad more under cut than normal if you use a round file...
We've heard a lot of people talk about the old saws not having enough rpm for chain speed...I've heard, and seen the same dribble about the 880 vs the 660...do none of them ever change their sprockets...I have both and can tell you...the 880 on a 25" bar & 10tooth 404 blows the 660 on a 20" & 8 tooth 404 clear out of orbit...so for your 1050 just try a larger tooth rim sprocket. though!!
One thing I've noticed...there is a particular chain speed that lets the chain set in the wood really good in the cut about 6000rpm on a 7 tooth...and it cuts quite course grained pulp vs the much finer grain dust at the higher rpm...and the speed through the cut is about the same...and the saw uses a little less gas in the process...so I'd have to say its cutting more efficiently and probably saving wear on the chain...un-decided about the strain on the powerhead and its a little tricky to keep the right on the ideal rpm.