I throw putters frequently. I personally average 250-275 for distance. I struggled with throwing putters up until I entered a Superclass tourney for fun. I was turning over that Zephyr bad. I changed to a fan grip, brought my index finger out on the bottom edge of the rim, released with a little hyzer, slowed my motion to be smoother. Now I rarely pull out my mids unless it is a lowline glide shot, or 275-300. I use a Star Rhyno, RFF Wizard, and SSS Warlock to putt, shoot upshots, and drive with. I can get around 300 if I let the Warlock snap with some good air and perform its full helix, but it takes a lot of real estate to achieve that distance.
I would suggest playing some rounds putters only on you favorite course. I found it shocking how well I did. Sometimes I beat my Personal best on the moderate courses playing just a Rhyno only...