just use the CP100 should be fine, unless you want a forward mid then I suggest to get CP800.
now also, CP800 must be the correct size, after I know that I could refund ear tips on Amazon, I purchased them from Amazon instead.
With CA16 since the nozzle is long, if you felt the CP800 very uncomfortable, get one size larger.
It's a preference, I think CA16 deep insertion rivaled those of Shure/Etymotic.
Now if you purchase one size larger, CA16 will not mold into your ear pinna, it will be slightly coming out from your ear. This is actually good, it will not obstruct the front vent and you will never get a muffled sound. But the drawback, you might look a bit funny in the mirror with two ear monitor slightly sticking out of your ear.
If you have a very deep insertion, a caution, you may have to fiddle with the placement of your CA16 when you felt the sound muffled. It just means the front vent was obstructed by your ear, it stuck too close to your skin and prevent the air exchange.
Hope this help...