Does this make a difference? Could a layer of 3mm ruby balls above the cartridge heater work for thermal accumulation? I know longer heat up time but it may work to store heat. What are your thoughts?
It indeed does!
The strip of rolled up stainless steel fine mesh forming the poncho around the cartridge extends the heater's surface right up to the inner wall of the heater cover, quickening & intensifying the conductive heat transfer to the steel tube itself, which serves as the only relevant part for heat retention here. The fine mesh fulfilling the exact same function there as the battery of small basket screens, @Alan
stacks around his 7/16" Hi's cartridge heater and also around those in his various GTR units.
Same principle!; bit different execution!
The 'naked' 7.5W cartridge has merely a diameter of ~6.0mm and a length of ~20mm. That's fine for working within the smaller, more narrow 3/8" (9.5mm outer diameter) ss heater covers, which only have an inner diameter of ~8.0mm.
Using it within the 7/16" (11.1mm outer diameter) ss heater cover (or even larger glass heater covers) spotting a ~9.5mm inner diameter, the larger volume air flow can quickly overpower the small, 6.00mm diameter cartridge heater then.
Extending its diameter to a fitting 9.5mm & enlarging its heat transferring surface area with either a poncho of rolled up ss fine mesh or a battery of stacked ss basket screens solves that problem nicely & effectively, as the air must travel now through all the heated up layers of fine mesh or stacked screens first on its way to the load, while at the same time the steel tube itself (serving as kind of a heat storage battery) regains its thermal equilibrium more quickly after each hit, for the vape to be ready for its next hit.
It's a quite minimalistic & elegant solution, doing away with all the redundant thermal mass robbing heat from the equation, while still providing exactly enough heat & evenly heat distribution to allow you to even roast relatively large loads in a standard 14mm/18mm glass bowl quite efficiently now, as the GTR concept convincingly proves. That allows us to produce kind of a semi injector style vape experience, while still using a relatively small cartridge heater, limited to a 7.5W max output at 12V and Logs, that are lightweight as a feather, if need be
Having built some heavy duty injection style vapes myself (to rival my Herborizer XL & Ti), I'd clearly say, that a Log vape using the above mentioned principles can rival them only so far, as the heavy duty injectors use a) larger heaters with a higher wattage output (usually around 15W-20W) and b) a good deal more thermal mass for heat retention (be it simply more ss, Ti or adage of glass/ruby/quartz beads), that allows for projecting the heat over a greater distance from the heater port, while also adding a good deal more conduction to the bowl, which usually improves rapid vaporization.
Question is... do I want to go there with my Misty Log
As I'm personally more the micro doser anyway, I frankly have no great interest there and find Alan's concept of 'more heat at less wattage' far more appealing
Also, with the CouchLog and the MUSA V2 (halo), there are at least two other German country men & Log Makers, which with adding glass beads around the heater port, already produce what you've looking for