The sableye idea is pretty good, imo. But idk if you need to go that far for the threat of sabledonk. I woud just add in a few more high hp basic techs like dialga, roserade, weavile, blaziken, etc. It should still be safe to play a lc not teched out against the donk.
IMO:
1.) Drop 6 cards
Playing 4 Sableye doesn't just protect you from the donk, it steals the first turn. With the rule changes, there is now zero disadvantage to going first. A T1 Collector, followed by an energy drop, followed by Impersonating for a Cyrus, Energy, and Power Spray could spell huge trouble for your opponent. In my opinion, 4 Sableye is a must in BW Luxchomp, and Call Energy just lost a ton of viability since you can't Impersonate AND Call T1.
First off, playing 4 sableye doesn't protect you from the donk. It just decreases your chances. If there was a rule that said "if you have 4 sableye in your deck, sablelock is not allowed to beat you", it would be a good play. But making room for that many cards is pretty tough without sacrificing for every other matchup. Plus if you do steal the first turn with sableye, you still need a way to get more basics out that is already in your hand. It's already been said that you can't impersonated anything to your bench.