Yes, use the stock servo arm until you can get another set up. Something like this, https://www.amainhobbies.com/hot-ra...steering-w-25t-servo-arm-hraaon48sh25/p702009
Will that help with the "level-ness" of the linkage too? As @Rott mentioned, the link that attaches to the servo arm seems to be at a bad downward angle when I attached it to the servo arm you supplied. That's why I used the taller stock setup that the small link attaches to the bottom of.
Sorry if these are rookie questions, but I are one.