Your deadlift co-efficient is around 2.65... this is around my personal best as well. I use the same grip as you. If grip is your biggest problem at this stage I have a feeling you'll be able to lift a lot more on your deads than your personal best. Do you use chalk? I've never had a problem with grip when I use chalk and a good bar. Also, prior to the lift kinda "lock yourself in" to the bar... I mean basically just chalk up, and twist your palms onto the bar until it feels like the bar is almost a part of you. Its weird to describe, but once you start doing it, you'll know what I mean.
Not all bars are created equal. Make sure you pick a good thinner bar with good grip. Powerlifting bars are fantastic. Not sure if you've ever had the chance to work with an actual powerlifting bar before.
Thats' pretty impressive that you don't rest the weight on your clavicle after your clean. For my clean and press I always rest it on my clavicles prior to going for the press.
Anyways good job man, keep it up!