Tinkering w/ Light Crossbow. Thoughts??

Pretty new to playing D&D and playing a Rogue who uses crossbows and bows with Sneak Attack.

I recently have been trying my hand at Tinkering with some ranged weapons and figured my Rogue could attach/mount a spyglass to the top of it to function as a scope. Pretty awesome, right?

My DM approved of it, but we have yet to fully hammer out the bonuses to the Light Crossbow (in this case). I'm thinking: +2 Attack Roll Bonus 19-20 Nat Crit Range

• 10-20% max range increase

What does everyone think? Any suggestions?

BTW, I just hit Lvl.6 and am multiclassing to Fighter for 3 levels (Archery fighting style & Battlemaster Maneuvers), and I have 3 Feats - Resilient, Sharpshooter, & Crossbow Expert (skipped ASI and swapped Skill Proficiences from multiclass for feats).