These days, if you should visit me in the basement of my house in South Qeynos, you might be surprised to find me slaving away at my workbench, chipping raw gems into jewelry while wearing only the rags that I came to the Isle of Refuge with. Why I might do that is worth posting about, since its a bit counter-intuitive, to say the least.
Take a look at this screenshot first. It shows some buffs I can use to increase durability of an item during a crafting encounter. In particular, notice that the power cost for casting Rose Cut is 1067, and Radiant Cut costs 800 power. My current power max is 5336. This shot was taken with all my gear, jewelry, and buffs going to enhance my power.
Now, look at the next screenshot, which was taken after I took all my gear off, and cancelled all self buffs, except for my Breeze. The power cost of Rose Cut is now shown with 463 power cost, and Radiant Cut with 347. My total power is listed in the persona window as 2315. If you calculate the ratios, you will find that 1067/463 = 800/347 = 5336/2315 = 2.3
The conclusion is that power costs for the Rose Cut line (and also for the line of spells that increase progress at the cost of power) are a fixed percentage of your total power, NOT a fixed amount of power, as combat arts and spells are.
If you try to confirm this yourself, you must be aware that the examine windows don't necessarily update when you put on or take off gear. Best is to change your gear, wait a moment to see that everything has updated through the server, and then reexamine the relevant tradeskill arts. I've seen some oddness here, mostly because things are slow to get the message that your pow total has changed.
However, power regen buffs, such as from Breeze, cannabilizing, and drink give an absolute number of power gained each tick; the benefit from them does not decrease if my power maximum goes up or down. This is why I want to get better drink as I level up and my power maximum goes up.
Are you getting the picture yet? If I craft nekkid, my power regen becomes much more significant compared to my power costs and my maximum power. Probably for modesty's sake, I will get one of the decorative outfits available in town, or who knows, maybe two or three, and craft in them. But having no enhancements to my power is clearly advantageous for crafting.
These screenshots will allow me to discuss one other tradeskill nuance. I'm a durability crafter, not a speed crafter. I don't knock speed crafting, but I like to get pristine quality every time. I think this comes from making spells the old way, where pristine was desirable to get the higher quality spell, and it was necessary at each stage of ink making.
The method I finally developed that works well for me consists of using the art that increases durability at the cost of success chance (e.g. Locus of Spirit) as often as I can. If I need to counter with another skill, I will use the one that increases durability. And I will blend in the art that will increase durability at the cost of power, such as Rose Cut, when my power is at or near full. This gives me a reserve of power to counter a chain of events, or in case the durability drops below pristine.
But, I find that I prefer Convergence of Spirit to Locus of Spirit these days, in spite of it's being lower in level. Convergence of Spirit gives me +5 extra points to durability every cycle, while only costing me 2 percent of a failure. Well, a failure costs 50 points of durability (before the effect of any tradeskill), and a success costs 10 points of durability, a difference of 40. Two percent of 40 is .8 of a durability point. But I get 5 extra points of durability, so that's a net positive of 4.2 points of durability each time I use Convergence of Spirit instead of Locus of Spirit.
Not convinced yet? Using Convergence of Spirit by itself builds up my durability roughly twice as fast as Locus of Spirit. Each cycle that I get a success while using Locus of Spirit, I gain 5 points of durability. A success with Convergence of Spirit gains me 10 points of Durability. That's a big big difference. The difference in success chance is really pretty small, not nearly big enough to make me want to use Locus of Spirit.
I should add that at some point in the combine, I switch over to using progress buffs, just to speed things up. But only after I've built up a cushion of extra durability. And never until I've filled the first progress bar.