Hi there, I'm Matt Sergei (do call me Matt, please) and you need relatively easy changes in several chart definition lines for RTL text captions and tooltips.
I prefer fixed rate projects since hourly based (for non on-going work compared to IT support etc) aren't fair for either party.
So one hour will be tracked (20 EUR/h after Freelancer fee, I'm incorporated) unless there is significant amount of additional work required. In that case max. 2 hours will be tracked with Freelancer desktop software.
Otherwise I'm a webmaster and IT developer for 26 years, scripting web animations/charts/visualizations for 7+ years, including HighCharts charts.
Regards and hope you're safe,
Matt