I've been playing a ton of Splatana Stamper and wiper since the game released, I only used wiper in the splatfest premiere and mained wiper and stamper since the game has came out, so let me show you some tips and tricks i have found to using this fun and funny weapon.
Number 1: this weapon isnt a tetra dualie, dont be dumb like i was in the first month and rush into fights. this weapon not only has a high ink consumption but has trouble fighting against weapons with fast kill times like shooters. Try to instead out range these opponents.
Number 2: Don't go for that one hit. It goes without saying that the one hit with stamper is sooooo fun to use and satisfying. Though it isn't practical and shouldn't be gone for unless you get a really good flank, or your forced to because your in a close range situation. If you'd like to do stuff like this use a roller, or use wiper as its way more practical for it even if you still shouldnt do it most of the time.
Number 3: Horizontal slashes are great. I see a lot of stampers not using normal slashes in situations where its really good to do so. For example: if your close to the enemy enough so that your normal slash can hit after a charged, do it instead of your burst bomb. It saves you a lot more ink which can be consumed quickly with this weapon.
Number 4: Zoning is key with stamper. You can easily outrange tons of shooter weapons, sloshers, tetras, etc. use your range to the advantage and zone these weapons out allowing for quick and satisfying kills.
Number 5: Know when to use a burst bomb. If your using stamper burst bomb is very good to be using but know when to use it over your horizontal. For example say you can reach somebody with vertical but not quite a horizontal, throw a burst. Somebody hiding behind a wall that you cant arc over since its stamper? Throw a burst bomb! Its a great way to flush them out.
Number 6: Hide your zipcaster, don't go blazing in headfirst and get killed instantly. Thats a waste.