Black border is a must talaga for a screen. Pero dapat talaga dark paint wall ang environment mo tapos white screen lang ang nakalitaw para to improve the contrast of the projected image, pero if no other way to paint darker your environment, lagyan mo nlang ng black border. I've already tried light gray paint, pero di ko cya type kc dumidilim ang image, Yes gumaganda ang contrast but I don't like the overall image quality. Pero try mo din kanya-kanya nman tau ng taste dba?
By the way, Led86 has also a keystone but same with your uc46 na useless nga, kc konting pihit lang blur na ung image. Ang walang keystone ay ang UC50 pero perfect ung focus nya for the entire screen. Kaya ng mas gusto ko image quality ng UC50 kaysa led86 ko eh...