Auto primary chain tensioner

I have a 2003 Heritage softail classic that i installed a HD auto chain tensioner on the primary chain. I followed the directions exactly but could not get the required chain slack as listed in my service manual. The auto tensioner is down as far as I can get it and I only have 3/8" of play on the chain. It remains the same 3/8" whether it is cold or hot. I have been told that with the auto tensioner, that the slack doesnt change that much and that I will be ok. I dont know if I am comfortable with the minimal clearance and would like to know if anyone else has experienced the same problem. I am seriously considering changing back to the stock tensioner.

The first thing ya gotta do is pull the spark plugs and put the bike in 5th gear. On a lift turn the rear tire in order to change the position of the primary sprokets checking the free play of the chain. Do this in many different positions of the wheel. The idea is to find the tight spot of the sprokets where the chain is the tightest. Do it until you have found the tight spot. If it's still the 3/8" slack, you won't have a problem.

Thanks for the suggestions. I will check it out this weekend.