I have small hands to go with my short legs
and I can't deadlift with straps at all. I've had similar experiences to you 5kg. On a few occasions, I couldn't get the bar off the ground wearing straps, I instantly ditched them and easily lifted the weight.
I could well be utilising the straps incorrectly. Also, Fazc has spoken at great length about grip issues being something of a warning about upper back weakness. He certainly has a point as my failed deadlifts have always been as a result of upper back/trap weakness.
Sod wraps and say yes to chalk I say mh:
Unless of course you're in one of the 99% of gyms that doesn't allow it