You may also want to play with seating depth a bit. Drop your load down and seat the 107s 0.020" into the lands. I have found on average that the match bullets prefer to be loaded this way. You do need to adjust your load though and work it back up as this will increase pressure.
Nothing worng with H-1000. Your pressure will be less as you are seeing but it will also produce a bit more powder fouling so keep an eye on that. YOu may need to clean more often but powder fouling is easy to get out quick.
As far as a rest, I use the Caldwell 1000 yard BR model rest. I like this rest as it is very solid, has interchangable top bags. Has ALOT of vertical adjustment and also a good windage adjustment system as well.
Its also reasonably priced. I would say its worth twice what they charge for it. Its not like the other Cadwell rests, this sucker is solid cast iron and weights 24 lbs. I shoot my 36 lb 50 BMG off it and the 28 lb Kahn and it handles them with ease. It will work great for my 60 lb 338 Allen Mag as well I am sure.
For the money its very hard to beat and in fact I like this rest better them some of the $400-$500 rests I have used.
For a rear bag I use a standard medium size rabbit ear leather bag filled with heavy sand.