with continental tires, you almost have to stretch the tire by hand and foot to get on a rim, even with both unglued.
what i do is grab the tire with both hand right next to each other. make sure the valve stem is between your hands so you don't put any pressure on that area.
then step on the tire, you foot should be opposite the valvestem at this point. now just pull up with both hands and stretch the tire a little. you should feel it stretch just a bit.
this will make it easier to slip on a rim. the tire unglued and an extra unglued rim works great. just leave the tire on the rim at air pressure until you are ready to glue it.
i let an older sprinter sit on a rim for a few months, re-airing it every once in a while. i glued it last night and it was still really hard to get on. continentals are just tight tires.
i use nitrile gloves to spread an even coat of glue on my rim and my tires with my finger. let the glue dry for about 20 minutes or so and then you can mount the tire with bare hands and not really get much glue stuck on your fingers.