Most people that I know of do not bother with the journals for Supreme level. What they do when leveling a new character is:
1) They produce the guild emblems they need ahead of time. Run guild recipes. That way the gear is ready when your character reaches the correct level.
2) They ask their friends to run the guild recipes. Each friend makes one or more pieces for them.
3) You can buy 100% critical chance scrolls in the Lotro Store. I think this idea is a waste unless you are doing level cap gear.
The scrolls require butchering massive numbers of humanoid mobs of the correct level. Stuff lives in Moria, Lothlorien, Mirkwood and Endewaith should be the correct level. You might find on the humanoids in Southern Eregion - 51+.
Unless stated otherwise, all content in this post is My Personal Opinion.