DBO1 caster blocks

[d16dcoe45]

I notice that the Dbo1 durga caster blocks look like virtual copies of the 501x WCE alloy blocks. Are the Durga blocks 10 degrees like the stock WCE ones? Are they exact copies (only plastic) of the alloy WCE blocks? If they are not exact copies, do they still bolt on to the 501x?

I am asking because I remember a few guys on here saying how they preferred the feel of the stock 501 plastic castor blocks over the WCE alloy blocks. I happen to like the WCE ones simply because of the extra roll center adjustments they give and would like to try them in plastic for the "feel". With the stock 501 blocks you lose the outer roll center adjustment.