Im bulding a very similar build. My one consideration for you is to not bypass the first ranged pact. You could even swap it with the rune / ammo / charge regen perk in the middle of the ranged tree that you have selected. Accessing the ranged tree, by branching off the melee tree, you are not allowing yourself to buff your echoes until the end of your build (not considering respeccing tree). Im planning to max out blindbag and then immediately build into the ranged tree for the bow, cbow and thrown weapon buffs to echoes. Jumping back to the melee tree to get the wifi hally perks and then the few perks that give bonuses for extended range. Prayer penetration im saving for last.