Could you weild 2hw in each hand? If you did both classes combined Or would you have to use a small sized spear/axe for a medium creature in each hand?
Would the alchemist (extra arm feat) change any of this?
You could wield 2 two-handed weapons with Titan Mauler thanks to its second level ability Jotungrip, which specifically allows you to wield two-handed weapons with one hand, but... The penalties for wielding large two-handed weapons this way are absurd.
Two-weapon fighting (w/feat) -4
Large two-handed weapon -5
Without the two-weapon fighting feat, it's -13 on the main-hand and -17 on the off-hand and you need 15 dex for the feat unless you go 2 levels into ranger or slayer, so it's a build that requires a high level character with good stats to be worthwhile.