Dual mining = less profit?

I think you’re required to mine 30% ETH and 70% another crypto in t-rex with dual-mining. I.e. you can’t flip it for 70% ETH and 30% RVN. The other crypto generally isn’t as valuable, whereas ETH constantly rises, making this less value then a strict 70% ETH operation. Further, dual-mining attempts to trick a smart hash-rate limiting program with variable shutdowns in LHR. Iiuc, solutions to this required underclocking the GPU to avoid hitting LHR limits. Single-mining until I’m convinced of a more profitable dual-mining solution.