Gripping with toes?

I bought a pair of glitter Pleaser heels a few months back and I was shocked to find that the surface of the glitter (the strap across the toes) was not vinyl.   I was also worried they would scratch my pole!  I showed them to an instructor at a workshop and she said they were good shoes--that they would also not scratch my pole.  Whew...  I have recently tried inverting and doing more of the moves I am comfortable with in barefeet, only to find that I can not grip with my toes in these shoes!  I was just wondering if it is normal to rely on my toe grip (moving from one inverted pose to another pose), or if I can learn not to need to hook my toe around the pole for more security.  Maybe it's not even necessary..?   Is anyone else a toe gripper, haha?  Any tips on what I can do differently? The shoes are very nice and I really want to get comfortable with them so they are more functional!  Not quite sure how to post a link, but this is an address of the exact shoe that I have: http://silvershoes.net/pleaser/pleaser-kiss-210-womens-silver-multi-glitterclear/