I’m glad someone found that piece of advice useful.Critical focus is a must for 4K sharpness. On a suggestion from Sage11x I use a spotting scope setup at the projector, to view the screen whilst focusing.
The monocular I use has a threaded base which allows it to be mounted to a tri pod (that to me was very important). I also recommend with this TK700 that you feed it a 1080p source and select game mode when focusing. This will force the projector back in HD mode and makes it a bit easier to focus around individual pixels (the pixel shift can make finding the edges of individual pixels more difficult). If you have a sharp 1080p image you’ll have a sharp 4K image.