So I recently bought a Yamaha Stage Custom bop kit. Looks and sounds great. But the bass drum (18x15) seems as heavy and takes up almost as much space as my 2000-era Tama Swingstar (22x16). Especially with the extra Gibraltar riser attached. Then, the riser isn’t comparable with my Ludwig Speed King (something other than the beater hits the bass drum head or the rim).
Bop kits are ..... well ..... bop kits. If you need or want one, then yes, they're worth it. I had two, for a while. A RMV 18, 12, 14 (still have) and a Yamaha 9000 series 18, 12, 16 (sold it). And if you think your Yamaha 18x15 SC is heavy (I currently have one of those kicks) ..... that 18" 9000 series drum was an absolute beast.
Now, most jazz guys don't use risers, so your Speed King (patent 1938) was happy to perform it's intended duty with bass drums that sat on the floor. My Speed King bolts up to my Stage Custom kick no problem, So, the incompatibility is (probably) the addition/introduction of a riser. My RMV lives on a riser, and I love it. The rear bass drum hoop does, however, have a cut out (see photo). And it's very common for bass drums on risers to have that feature.
But then there's .......
So...if it’s just as heavy, just as space-eating and I can’t use every bass drum pedal with it, is it worth it??? Another option would be getting one of those kits like the Yamaha Stage Custom Hip or Tama Neo Mod.
Bop kits were "space savers" in the good old days, because no bass drum was deeper than 14". The Ludwig Jazzette was 18x12. Depth is what eats up stage space. And finding a traditional depth 18 ..... you pretty much have to get into the high end lines for that.
So here's where you get to look at your "operational parameters" ..... if saving space is high on your needs/desired list, the two kits you mentioned might be better choices. The Tama's kick is 10" deep. The Yamaha's only 8". And ..... you get a 20" kick. So, if you're trying to find a substitute for your regular "rock" kit ..... I think these fit the bill better than a "bop" kit, that was, after all, more tailored for a different genre of music and tonality.