After you get a few more AG brews under your belt you will probably know the efficiency of your system. Then you can just add more grain to compensate.
As for this brew, I'd stick to DME. The dextrose will ferment out completely and dry your finished beer out. You might also end up with a less malty and more watery beer. Also your hops will be more evident. The hops part might be ok for an IPA but it'll throw the recipe off from what was originally intended so I'd just stick with the DME.
Beer is proof that God loves us and wants us to be happy.
- Benjamin Franklin (and I don't care if this quote has been largely discredited/misquoted...I like it!)
Beer, if drank with moderation, softens the temper, cheers the spirit and promotes health.
- Thomas Jefferson