There are my two personal DR.BT.
The one on the top is 20cm for 17 grams. It feels really nice, since my favorite mods are about 14-18 grams. Grippy barrels are my favorite too, since the 2016 summer. Tips used is from Pilot JuiceUp, a new pilot pen. Tip is 2.6gram each and looks like a big signo tip. It can fit easily on CT cap with some tape. Grips are from Needle point, sailor gel and anyball. Looks like a menowa* reimei with these long grippy side.
The one at the bottom is 18.2cm for 15 grams. This one was made for fun. Caps are made with hgg and beifa grip, stalogy backplug, airfit ring and signo backplug. I added stalogy backplug on each side of the barrel, for more momentum.