i mounted a compact SRM, maybe a year old, to an EVO a little bit ago. you need the lockring, or you can file the ends of the outermost part of the old one.
Although I do not have a Cdale EVO, I have been dealing with the SRM on a Ridley PF30 frameset and got a standard size '11 SRM hollowgram installed over the weekend. In my case, I opted to use an FSA PF30 bottom bracket which appears to offer ~1mm less inset of the bearings than the SRAM PF30 bb. Using the FSA PF30 bb, I was able to use the SRM spindle, SRM specific nds bearing sheild, and stock Cdale ds bearing shield which resulted in what I consider pretty 'symetrical' ds/nds spacing although the back of the SRM on the drive side is like nearly touching the pf30 shell.
The lockring issue has me curious as to why the comapct SRM would need a compact specific lock ring as my experience installing the standard SRM Hollowgram indicates that the bevelled part of the SRM's back cover is approximiately the same diameter as the PF30 bb shell. To me this means that the back cover would contact/rub the outer edge of the shell of the PF30 bb well before it touches the lock ring but since the compact is a new model, I am guessing that the back of the compact SRM hollowgram has a larger diameter hole thus enabling the spider to to seat closer to the bottom bracket shell than that of a standard SRM hollowgram.