I pin biceps with no problems.. learned not to do prop in them though.
I've been using a 29g slin pin lately with no problems. I just have to be sure to warm up the oil thoroughly before I draw and pin. I fill up a tuperware container with about an inch or so of water and throw it in the microwave for two minutes until its really hot. Then sit my vials in the water for a couple minutes then dry them off and draw and pin.
The more I learn and experience, the more I realize that, while there are some constant truths and guidelines, most of what we do comes down to the individual and how he/she reacts personally.
For me, prop doesn't hurt at all, 1ml doesn't hurt, (used to when I first started hitting biceps), and my oil slides easily through a 29g slin pin without heat (although the heat also doubles to help avoid knots as well, so it's not a bad idea regardless). I've never aspirated blood, never hit a nerve, and never had an infection. Like I said, this is all IN MY EXPERIENCE, so I'm not asserting any truths.