Notice how the recycling deck's bottom edge curves out, where the Hi-Vac's is curved inward. A bag or mulch plug can be installed on either deck, but each design is most effective when used for their intended purpose, mulching and bagging respectively. And although the side discharge shoot can also be installed on either deck, this manufacturer does not similarly have a model with a deck specifically designed for side discharge, so I have to determine which of these two deck designs will be more effective at discharging clippings through the side shooter- the HV deck with the inward lip, or the M deck with the curved out lip. -The Hi-Vac's lip-in design creates an increased vacuum under the deck, which supposedly sucks more clippings up the chute & into the bag. Since my side discharge chute will attach to the same opening as the bag's chute does, if we can assume that replacing the bag with the side shooter does not compromise the HV's increased vacuum, then a greater volume of clippings should similarly exit the discharge chute on the HV than the M... but can I make that assumption? I could see why not, since the bag with its chute over that opening is more "sealed" than the shorter, more immediately open side discharge chute. -The recycler's lip-out design seems like it would trap fewer clippings under the deck, & for a shorter duration than the HV's lip-in design would. How that affects throw IDK, but deck & chute bog potential seems like it might be higher. -Their blades are interchangeable, but each blade type is presumably optimized for use with its respective deck design- a multifaceted mulching blade for the recycler, & a single edged blade with wings that creates more lift in the Hi-Vac. As to how increased lift of clippings affects throw, I don't know. The recycler deck's multifaceted blade also creates finer clippings than the Hi-Vac's high lift blade. It seems like smaller particles would flow more efficiently, but they also might cling to deck & chute more. -Assume identical engines & drive systems. Bonus: Would the lip-in design increase structural integrity of the Hi-Vac's deck compared to the lip-out design of the Recycler? It seems like it would, but I'm not sure exactly why I think that. When I'm not careful enough maneuvering my current mower, especially on an incline, its deck twists enough to contact the spinning blade, & BZZT! If lip-in is sturdier in that regard, & I learn there'll be little to no difference in discharge efficiency between the two designs, that could be the tie breaker. Hate to trouble an engineering forum about my lawn mower purchase. I did ask in the pro landscapers' forums first, but since most of them mulch & bag exclusively, even those experienced with both models haven't compared their side shooting abilities. Any opinions, thoughts, or critiques of my thought process so far are appreciated. If this is more relevant to a different subforum, please move. Thank you.