Lookinforlunkers:
This falls into the "technical question" category and I will defer a technical answer to someone more qualified than myself to answer. From a "practical experience" perspective, I have been shooting and hunting with Black Widow bows exclusively since the late '80s and I suppose this qualifies me to at least offer an opinion.
Several of my Widows are of the take-down recurve variety. I can tell you that it is an UNDERSTATEMENT to say that the Widow take-down system is absolutely BULLETPROOF. As someone who shoots/hunts twelve months a year, my Widows get used and abused and they have never once - not once - failed me. Other than periodically changing the string, a few of my Widows have remained strung for fifteen or more years without showing any indication of fatigue. One of my oldest Widow take-downs has two sets of limbs- 42#s and 58#s. The first time I took the 42# limbs off and put the 58# limbs on that bow I can recall thinking, "Is the riser on this bow going to be able to handle this 16 pound difference?" Well, fifteen hunting seasons later, I can tell you definitively, that the answer is a hard-earned, resounding , "Yes!"
From a technical perspective, I cannot elaborate on the pros and cons of the Black Widow take down system. From a practical perspective, based on twenty years of familiarity with the Black Widow take-down system, I can tell you that there are apparently no “cons” to mounting the limbs to the back of the riser.