A reducer will work fine, if you can achieve a good seal with the bowl. It'll influence the flavour slightly, you really want to minimise or remove all metal and other reactive surfaces, but it's a good way to try it out and see if the Steinel method works for you. See how it goes - and if you want to improve the flavour and further reduce the risk of contamination you could switch to Vriptech's glass tools later on.
The VHW is light years ahead of the old Steinel method though - the flavour and purity just can't be matched, and you've got a lot more control over all of the variables like airflow, temps, heat soak (for radiant and conduction heat transfer, on top of the best convection I've ever experienced in a vape). You can get some very thick vapor by inhaling long and slow (much slower than the Steinel can do), or fast and hard for lighter vapor and more of a THC (vs. CBD) effect. It just opens up a whole range of possibilities that aren't really possible with most other vaporizers. I'm still blown away by the VHW and I've had mine for a few years now, after using the Steinel and Valloon for over 10 years berfore that. I can't see any other vaporizer beating the VHW to be honest, the only real improvements you could make would be for digital temp control, and maybe ground glass joints on the last remaining interface - where the bowl meets the reducer (VHW to reducer interface has a spherical ground joint coming soon).
I'd stick with the Steinel if you're happy, and consider a gradual upgrade path towards Vriptech's HG parts, the Valloon, or maybe skip straight to the VHW if you want better quality vapor on top of what you're getting from the Steinel. The Valloon's great as you don't need to handle the heatgun, just fill up a bag and walk away, and the heatguns are pretty unwieldy even after you've got your technique down. The VHW gives a much better user experience as far as handling it - just be sure to get the stand, I can't imagine using it without the stand as it gives you access to higher temps than the VHW can achieve on its own and makes it all very easy to hold and use.