I was just noting you already breed Partridge. The two varieties are crossed often to improve one or the other or just for diversity sake. If you want Silver pullets then Silver over Partridge and Partridge over Silver for Partridge pullets. Cockerels are yellow, usually not used.
If I had to critique the Silver posted I like the Cock, He's a fair tail and very good back line. The problem with the hen is her cushion. Notice how it bumps up mid back throwing off the sweep to tail. The Silver posted do have yellow legs and that is something the Partridge posted are lacking and if I remember you said your own birds needed help with leg color too. Picture I saw of one of your Partridge hens had excellent body type and little or no cushion. You really could make strides with both varieties having the pros of each at your breeding disposal. My opinion is you can't go wrong with these Silver Pencilled and think your Partridge and they would compliment each other moving both varieties to SOP. Seems a smart choice of variety considering your current flock and they are of very good quality.
To me of all hens pictured that Blue has the best body type. You can tell it's sub size along with the Blue cockerel but they both have great back lines and type. But then I'm really partial to Blue variety too so could be a little biased.