Not sure I'd describe Light Sussex a quick feathering breed. Good examples of the breed ought to be K which I think is called "late feathering"
I've had all sorts of Light Sussex back in UK where they are one of the most common breeds. They are generally good layers. The nicer Light Sussex are big meaty birds but many, usually (incorrectly) labeled as "utility", are small & not as typey. I suppose it is the same difference as reasonable examples of a breed & hatchery birds.
As Light Sussex (LS) in US are pretty uncommon there are not many to choose between. Of the LS I've seen in US, the only typey looking examples of the breed were being sold by a chap in Florida; I think, had imported them from Australia. These LS have been sold heavily throughout USA & will probably be readily available next year.
There might be other nice Light Sussex in US but, IMO, the other Light Sussex I've seen in US have been very much what are usually described, in Britain, as "utility" . One might compare this difference to the difference between reasonable examples of a breed & birds one might, often, get from a hatchery.