I Assume you have a GCLE or GCLEXL for your lesco. This catcher will fit the Cub Tank quite well. It will also fit many of the Scag mowers fairly well. You can always just put the catcher up against the mower to see if the openings match. The braket placement can be adjusted to allow for some variation in the openings. You can only carry this so far, however, as the mower opening needs to be the same general shape and length, and it needs to have the same deck depth.
As far as the deck tilt, fixed decks of this size have no problem with tilting, so if there is a system to make the deck fixed, that should solve the problem. You also can add a small 20 lb. counterweight to the opposite side of the mower (you don't need to counterbalance with a weight equivalent to the full catcher due to the fact that the counterweight has a mechanical advantage relative to the catcher, ie. the catcher is closer to the fulcrum point).