I've been using Lee moulds since they started making them. I own about 20 of them, and over the years I learned that what causes problems is lubing the mould.
I haven't lubed one of them in 25 years, and they all work fine.
The trick is to make sure the mould is absolutely clean and oil free to start, then leave them alone!
Lack of lube can screw up mould alignment as they are closed, and is really the only reason they "require" it. I align the halves as they close by holding a sprue knocker under the halves to assist alignment. It becomes habit after a while, in fact I now do the same thing with iron moulds.
If you're having trouble with the sprue plate tightening, it means it was set too tight to start with. Back off the pivot screw a quarter turn and try again.
Lube will eventually get into the mould cavities no matter how carefully it is applied.