ToME: the Tales of Maj'Eyal

So, can you have both?
In Demonolist guide told to take Tinker's craft skills, but my resently died (few hours ago) Demonologist didn't have slots for craftable devices.
So?...

They do not appear but are still there, so equip those tinkers anyway

Lolwhat?
You seriouse?
That's great!

They work, but fit into the same slot (i.e. you can't have seed and tinker on the same item... unfortunately) and as noted there's some UI shenanigans involved. Still, it's not exactly terrible on demonologist, from what I recall. Chunk of the stuff you want to stick seeds into either doesn't have (rings) or has crap (shield) tinkers, so you're still going to get return on the investment.