Blatantly parallel two tubes
Is that done?
Well yes it is done. Not by everybody, but it is (was...) done by the old Kondo Brand from Japan, and we see it often with others in the learning curve too.
As allways, this can only work if both tubes are fully indentical, age the same way, and start up the same way. If you are sure you can guarantee that, go ahead and perform the magic trick. But if you take my humble advice on this, with practical tubes, I mean such that you have to buy, this is very unsafe, and you can get trouble, either right away, or later if the tubes step by step begin to take damage, or finally if one ages not the same as the other. A good parallel circuit always has a way to correct individual bias of each tube. EIther by auto bias, or by adjustable bias.