by stacks, are you guys having separate wallets for each "stack"? I don't know of any other way to separate the coins into "stacks".
you can combine multiple blocks into one by sending your chosen amount to yourself. any number of blocks can be in the same wallet, even the same address.
Using coin control (which is under the send coins tab) you can choose what blocks to combine, which to exclude. It's fairly simple in it's mechanics. We in the high staking coin community have quite a widespread debate over the best strategies, but the short form is that bigger blocks have a higher chance of staking first than smaller blocks. It all comes down to how you choose to stage them. TEK is a pretty forgiving coin, so do what thou wilt. Some of 'em are picky in what stategies work.
I don't see a "send coins tab". There a send coins button, which opens a pretty normal QT wallet send coins interface GUI. I don't see a "coin control". I'm in the tekcoin -wallet (don't know where else I could be). I'm not sure I would do anything, but I would like the knowledge.
