I fitted some Speedymoto Tallboys clip ons as part of a crash repair to a 1997 Ducati Monster 600. One of the issues with the pre 2002 Monsters and clip ons are the top triple clamp screws which sit at the outer front edge of the triple, exactly where most clip ons rise to the bar clamp. The 2002 on models have a rounded edge and the clamp screws is moved to the front and inside of the fork leg. So for the pre 2002 you either have very low bars or lift the forks up so you can put the clip ons above the top triple. Which makes the front even lower and reduces the rake. Or replace the top triple, which starts to get (even more) expensive.
The Tallboys get around this by the placement and style of their risers. As fitted to this bike, they are as low as possible and can come up another 32mm if slid up to the bottom of the top triple. So they're not a huge amount lower than the original bars. However on this bike the originals had been replaced with some higher steel bars, so they were definitely quite a lot lower. They're also quite wide, which is the thing that really struck me when I first sat on the bike.
But when out riding it didn't feel too unusual compared to my otherwise identical M600.
The photos show them fitted at their lowest possible setting.