Currently, I am not aware of Spot FX working over Rithmic, and Optimus Futures only works with exchange-traded products when it comes to Rithmic.
The same applies to CQG, they use Currency Futures over MT5, and we are not using them for Spot FX.
As a retail trader, you do not have the tools to grab latency arbitrage because you need subpar microseconds, which requires serious investment in architecture hosted near the CME server. In addition, due to cost, you will need to at the very minimum to lease a seat on the CME.
Lastly, latency arb is discouraged by spot FX providers, and most likely, they will disable you.
Many see that as a violation of fair pricing and dealing.
My recommendation is to work on a simple method that is not time-based (arb) but has an edge.
I hope this helps.
There is a substantial risk of loss in futures trading. Past performance is not indicative of future results.