Skip LATCH and go with a ClickTight seat. LATCH is limited to something like 65lbs including the seat itself which can easily weigh 25 or more pounds. ClickTight? Limited to the seatbelt strength. Side bonus, you literally cannot screw up the installation and it works with any seatbelt from pretensioners to old skool lap belts. All the locking is done within the Click Tight system.
Downside, they are spendy. I have more wrapped up into the car seats (infant + spare base and two convertible seats) than I paid for both cars :lol: