Advice needed for finding backfocus for ED80

[kookoo_gr]

Recently i bought the Falcon rotator from Pegasus astro and i do not have sufficient backfocus at my ed80 and i would like some advice.

I have the old ED80 with the stock focuser which has a leght of 90mm, the drawtube extends at 17mm and i have a baader clicklock 36mm in length.

 

My current imaging system has an astrotech flattener which has a lenght of 41mm along with the adapter that  connects to the falcon rotator. The rotator along with the extension i have put, since the oag focuser ring is to wide, is at 47mm As you can see from the photos the total backfocus i need is about 88mm which the focuser cannot provide. I would like some opinions on how to find 71mm in order to focus my imaging system on the ed80. Is there a shorter focuser for the ed80? Maybe a combination of focuser and flattener?