I have the same keyboard (with a Kinesis keyboard tray) and while it's not as sloped as yours, I'm maxed out on negative angle (while sitting). The most import

I have the same keyboard (with a Kinesis keyboard tray) and while it's not as sloped as yours, I'm maxed out on negative angle (while sitting). The most important thing is that the keyboard height and slope match so your wrists are straight. In general, I prefer having my elbows more open because I find that minimizes arm fatigue, but having the elbows open would definitely not be a plus if it forced your wrists into extension.