Unfortunately I dont have the answer you are looking for, but I have been in the litecoin community since the GPU days, and what I do know is that litecoin has consistently been the most stable and profitable coin in all of crypto currencies.
For the last 2 years or so anyway. It's been impressively stable - but it's also had ZERO new gear showing up for most of that timeframe to drive hashrate and difficulty up.
I've also gotten a sense that there might be a major mining whale out there that's been actively trying to keep the price stable (on a $ exchange basis, not on a BTC exchange basis) to keep their competition low enough to drive out most of the less efficient mining hardware while maximizing their own mining profits.
im constrained by power capacity
I have the same issue, but I am also constrained by lack of available capitol.
The incremental cost of the L3 for me makes it not an option for the forseeable future, no matter how profitable it is - even if it turns out to be S5 level reliability or better instead of S9 unreliability level.