I have a viper and it is the best stand by far ive ever owned, but i dont think you could use a bowholder and it would be difficult to shoot while setting, i usually stand. You might want to check into the summits that fold down to carry, and if you go with a bushmaster or i believe cobra you wont have to worry about the bar...
if your only use to 12lbs then i would try to get the lightest summit they have because yes you will notice more weight...
good luck, and im sure you will like the summits....