Exhausting choices

I have 2 ways of venting grow room from upstairs crawl space. One is 3" vent to roof BUT will be approx 10' horizontal and 4' vertical out to roof. The other is approx 1 3/4" pipe used for plumbing drains (p traps) that is only about 6' run to vent out roof. Which would you choose? I will probably use a 4" 170 cfm vortex with reducer. I guess this will make it work harder but seems like a good unit and I need a quiet one. Have not seen ones capable of moving much air smaller than 4" except cheap loud ones.

Decided to go with 3" vent. I live in a somewhat rural area. Me and all my neighbors have 2 plus acres each. Since I am exhausting out roof and nearest neighbor is about 200 feet away I am wondering whether I need a filter. Sure would get alot more air pulled out of grow room without. Just not sure.