All I know about warrants is that they have costs,spread,time decay and gearing. If you get it right it's great, but if you get it wrong you will get carried out of here in a body bag. Unless you are already a good trader you shouldn't touch warrants. Just my opinion (from bitter experience).
Delta can't be changed by you. It has to do with the correlation between the change in the warrant value and the underlying share - in reality - it is the result of a lot of other fun machinations including time to expiry, volatility, the underlying strike price and another derived measure, the rate of decay. European puts are only exercisable on expiry date - but don't worry - in my experience there will be nothing left to exercise by then. In theory they are cheaper than American style and since you can trade the warrant in the market - it makes no difference anyway, I suppose. In my humble opinion warrants are a load of opaque nonsense so heavily tilted to the house that you need the stars to align before they work. They have some value as hedges in a market moving event, I guess. If you are confused - good - that means you are sane. Maybe look at CFD's/ futures and manage your margins very aggressively..(?)
Warrants are so yesterday and like Russ says they a crazy instrument to trade, that time decay is a killer! If you want gearing trade cfd's where the on;y time decay you need to be concerned about is your age.
People don't view the warrant as a package of upfront interest - so it is easy to understand why they view the decay as artificial. Given that under certain circumstances - the warrant loses all traction on the share price but continues to decay as before - they may even be Right! These are very "sophisticated" instruments. Even if we were given proper access to the calculations behind volatility adjustments, disposals as the price of the underlying drifts away from the strike etc. etc. etc. - it is all just way to complicated and - ultimately - you rely on the house to act in your best interest - that kind of abdication of responsibility tends to end one way! I know a bit about this silly game - and I wouldn't touch these things with a barge pole. I am always amazed by queries from people who lack knowledge but want to start trading in warrants... on the sell side, no less...