Well, well. Yes it's a new army but one I have had for a while in the to-do pile, not jumping in Horus Heresy yet, just fancied a change of colour and watching a few YT videos to find a method and scheme I like. Here is my latest purchase, an eBay job painted as a White Scar Legion however with a change of trim and shoulder pauldron and a test of a YT 'Marine Juice' for weathering I give you a Primus Medicae in Cataphractii Terminator Armour.
So the original model when it was released I thought of one Legion and one only, it screamed Death Guard, its leather apron made the model look to have a distended belly like corrupted Death Guard, I liked it and once I had made my decision to choose a Legion, Death Guard it was - in some small part to this model which was then OOP... so I hunted for a fair priced one on eBay and the above was a good (enough) price and decent paint job. Instead of a strip and re-paint, I opted for a modification and wash.
Metal details were picked out in Decayed Metal - from Scale 75, a totally awesome metal for Death Guard Legion. The blood transfusion bags I opted to keep the turquoise wash the apron was and overpainted the apron with whites and contrast Skeleton Horde. The plain pauldron was a test for the Death Guard scheme, Death Guard Green (obviously), Nurgling Green highlight and edge of Kreig Khaki. 
The base was Stirland Mud with a Baneblade Brown drybrush and a black rim. Different from all of my 40K armies using Calthan Brown/Mournfang Brown base and edges.
The best thing is I really liked the scheme and the sickly green. I will get some test models done for Tactical Marines but before I forget or misplace the recipe I will be using:

Undercoat - Spray Chaos Black
Basecoat - Heavy-ish Zenithal spray Wraithbone
Greens - Death Guard Green, edged Nurgling Green, corner highlights Krieg Khaki
Metals - Leadbelcher, highlight Iron Hands Steel
Weapons - Black then Leadbelcher on metal parts, highlight Iron Hands Steel
Eyes - Blood Angel Contrast
Chipping - Rhinox Hide, White Scar on lower edges of big chips
Trim - Scale 75 Decayed Metal, washed AGrax/Terradon Turquoise 4:1 ratio, Balthasar Gold Highlight
Wash Everything - Marine Juice (Nuln Oil/Reikland Fleshshade/Lahmian Fluid 1:1:1 ratio)
Rust spots - Streaking Grime and Thinners
Base - Stirland Mud base, drybrushed Baneblade Brown, Black rim

Cheers, Siph (10pts)