smoke in eyes

[smokezilla]

Hello, I have been watching forums on this site and want to know if any body could solve my problem. I own a char griller and have done mods i have read in forums, sealed sfb and main chamber stack to grate level made baffel out of aluminum pan and lined bottom of main chamber with ceramic grill bricks. I have been smoking with this settup for 8 months with great results, temps. from end to end are within 5 degrees. recently i put 36 inch ext. on stack to keep smoke out of eyes. I smoked a 10 pound pork shoulder picnic yesterday using royal oak lump in basket adding hickory chips for smoke untill temp. of picnic was 160, temp. of main chamber was between 225 and 250 for 11 hours then pulled out at 195 wrapped in foil and towel for 1 hour and pulled meat, was very tender and tasty but very little smoke flaver. I was wondering if stack ext. created to much draft and sucked smoke out to fast, i allways smoke with stack wide open, any ideas, thanx