One of the other problems that tinker has is that cube's traditionally don't have a high artifact count
A handful of the best ways are Virtue of Loyalty, Chivalric Alliance, Forth Eorlingas!, Court of Embereth, and History of Benalia
DJ Johnson: I love the black and green color combination
if you assume, on average, you're drafting 31 playables for your deck (23 spells, 5 lands, 3 sideboard cards) then approximately 10% of your cube could potentially be strong sideboard cards and the resulting decks would be 'more powerful' than a cube with no sideboard cards
Although it can't prevent combat damage that would be dealt to your planeswalkers, it can still prevent noncombat damage that your opponent would want to redirect from you to one of your planeswalkers