Yeah, height is a bit of a dilemma, even with the longer lamp arm extension on the VeggiePro and similar "tall garden" AG models. I love the sativa high, that's why I want more sativa-heavy plants in my grow--even with the autoflower strains, though I know all of the autoflowers are probably no more than 30%-40% sativa, at best. Seems like most of the autoflowers tend to be primarily ruderalis/indica hybrids, with maybe some token sativa genes thrown in there for folks like me. I know they have to mix in the indica and ruderalis to keep the plants short and bushy and give them the autoflower capability of the ruderalis.
But I'm on the hunt for a clear, uppy autoflower high, so I'm just going to experiment with as many of the different autoflower strains I can, and hopefully find one that one with just enough of the sativa high to give me what I want out of the smoke without the pain of wrangling with a tall sativa plant that outgrows my AG. Hopefully the Auto Assassin will meet that criteria.
Let me know how your grow goes--it would be great to get a preview of the plant since I'm planning to do that one next.