You may get more of a responce from the CRT Projector folder.
Your Quadscan can only accept none interlaced PAL (525i) or NTSC (480i) so is not HDTV compliant. You would not use the scaler with HDTV material anyway as it is already at 720p/1080i/1080P. You would connect the HDTV device (HD sat box, HTPC, D-VHS) directly to the PJ.
Your Seleco can accept RGB upto 38Khz and therefore should be able to accept 720P/1080i. But I would check this first.