Thanks again for the tips, Jonathan. I just ordered the ASTF 140 for my 600/4 II, the ASTF 120 that will fit either my 100-300/2.8 (600/5.6 in this scenario) or my daughter's 5" reflector telescope, and a pair of ASBF 50's for my Canon 10x42L's. I also ordered a pair of screw-in aluminum hoods for the binos, the Canon design for the two pairs I have (10x42L and 10x30 IS) is such that there's very little objective lens housing protrusion on which to push-mount the solar filters compared to 'typical' designs like the Nikons on the left.