I am interested in putting an illuminated Leupold VXIII 1-5X20 on my 45-70 for black bear hunting and who knows what else. I noticed that they are available with a 1" tube or a 30mm tube. However, they both have a 20mm objective lens. I "assume" that means they are equally bright. Other than more reticle adjustment; what would be the advantage of using a 30mm tube? Any suggestions on this Leupold or similar scope for use under 200yds?