Get a Weighted arranger like I did (Roland Piano KR577)88 keys but very heavy though. Or maybe a more portable offering in the Roland KF90 - which has a fully weighted action. I too have an acoustic Piano (Brand new 6 foot Grand Piano - just 2 months old), and stepping off the Roland doesn't require much adjustment to my technique - if at all. I also brought a Triton Studio last month, and whilst not weighted, are very good keys for a synth. However, *NEVER* practice scales/Piano solo's on an arranger (non-weighted)if you are to play it as a finished product on a piano proper.

Also, I may add, don't let the arranger function determine your style, its all ok pressing panel A, section B, and have Glen Miller & co' invade your life for 3 minutes - with little help from yourself.

Tony