one thing that hasnt been mentioned in this thread is the O rings that should be in the cups - if they are not there then try fitting a 1-1.5mm long slice of duel line - it makes a lot of difference by helping to prevent the cups binding on the dogbones which is what we believe causes the breakages...

...along with excess suspension travel, u can limit this with fuel line inside the shocks on the shock shaft for excess droop, or zip tie the arms to the towers. with excess compression try fuel line on the shock shaft, outside of the shock body. or remount the shocks in a different hole in the towers, and try that.

frustrating innit? if u get real stuck, i have some perfectly sized olives/compression fittings here that are available for cost + P&P.... should be available in oz as they are metric tho - 10mm are the ones in case u didnt know, from the plumbing section of ur local hardware store.