From levelling to a 350 transmuter I took note of what kind of percentages I had for skill ups on each con recipe.
From my experience:Grey Transmuting Recipes give approx a 23% chance to skill upGreen Transmuting Recipes give approx a 30% chance to skill upBlue Transmuting Recipes give approx a 42% chance to skill upWhite Transmuting Recipes give approx a 54% chance to skill up
The higher the level transmuter, the higher tier recipes, and therefore the more expensive the materials.
As an example, creating transmuting recipes at level 325:
Tier 1 Treasured Adorn (Grey Con)
Ulteran Powder x 1, Lapis Lazulli Fragment x 9
Market Value for materials - 10g for Ulteran Powder, 18c for Lapis Lazulli Fragment (2c each), 10g 18c total cost
This gives roughly a 23% chance of skilling up at a cost of 10g 18c
If you compare this with a white con recipe....
Tier 7 Treasured Adorn (White Con)
Illusionary Powder x 1, Lunar Fragment x 9
Market Value for materials - 45g for Illusionary Powder, 45g for Lunar Fragment (5g each), 90g total cost
This gives roughly a 54% chance of skilling up at a cost of 90g
Following this, if I create 20 recipes I'm looking at:
T1 - 20x Grey Con Recipes
Cost: 2p 3s 60c
Skillups: 5
T7 - 20x White Con Recipes
Cost: 18p
Skillups: 11
Grey con recipes are by far the cheapest way to level transmuting, however no matter what option you choose to take transmuting still costs you A LOT of plat. Personally I think the only time it's worth levelling a transmuter is if you are doing it to help out your guild. Way to expensive to just level for the heck of it.