I have one "standard" 801 drip tip, out of several that has a short enough extension below the o-ring that it will work on the oldest/shortest mini. I have no idea where I got it, though. I think it is a "rare" one. In the meantime I'm using the soft rubber whistle tips. I've only done the 3.5 semi at 6v and there is enough height of tube for the standard tip. For one of my Mini the soft rubber tip, that came off of an 801 cart, needed a little trimming at the bottom. They are easy to trim with sharp scissors. (DH vaped 801 pen-style from August to Dec so I have a few soft WT I didn't
throw away from the 801 carts.
If I was going any higher in ohm than 3.5 and had an issue with the DT being too close to the bridge I personally would use only Delrin and dremel off some of the bottom of tip. The metal tips aren't going to burn but don't know about the o-ring, it might get to hot for lips, and you could potentially have other issues with the metal tip touching the atty.
I have started cutting down the length of the IKV 2.0 801 tall/standard to Mini and Semi size. (I love them so much I snapped up 20 of the remaining 40. Someone else i know picked up 10 of the last 20. We love our IKV 801 2,0 ohm attys) I cut one a little short so I had to trim the soft rubber WT bottom a bit. But I haven't done this yet with the HV 801.
There's a lot of curiosity, lately, amongst the Reo community, and lots of people want to try them on their bottom fed Reos, standard and Mini 801.
Alice