I can tell you that the Unity version of Starmada SFU is the most true to the original ADB incarnation of the SFU - it plays much more like FC/SFB than the earlier versions (in a good way). It is hands-down my favorite SFU game, ever, and I started with Star Fleet Battles in 1983, and eventually made the move to Federation Commander. Everything from firing arcs to movement to the way that weapons work and damage is handled is much more "SFU" than the earlier editions. If I were you, I would bite the bullet and invest in the three Unity books that are currently available. If you are a fan of the SFU, it is the best $40 you'll ever spend.

Having said that, there is a guide to converting between the early editions of Starmada and Unity - look for it linked in this thread: http://mj12gamescom.ipage.com/forum/viewtopic.php?f=2&t=12672&p=41295&sid=1d359679e06002258cc7a0229a74d20a#p41295

There should hopefully be a Unity version of Distant Armada coming soon, as well.

As for your question re: movement, I never played non-SFU Starmada, so I can't really answer that. I will, however, say that I constructed a 10-impulse movement chart for Starmada SFU that I've used with great success. Let me know if you would like me to post it.

I haven't found that it slows down the game much at all - remember, in Starmada movement and combat take place in different phases of the turn, so you don't get to (potentially) fire weapons every impulse (or 4, in FC). I use the impulse chart with free movement - it allows faster ships the chance to position themselves based on how the slower ships are maneuvering. I tried posting it, but the board won't let me post a text file (?!?), so I'll make a pdf out of it tomorrow and post it then.

In the (highly unlikely) case that a fast, undamaged ship might buy some extra movement or utilize the "no phasers" option and thereby end up with a speed greater than ten, I would just add the extra hexes of movement to impulse ten - i.e., have the ship in question move two or three hexes that impulse, whatever is needed. In practice, that will likely never occur, since the fastest object in SFU Unity that I have seen so far has a speed of 8.

When multiple ships are supposed to move at the same time, they go in order from from slowest to fastest.

Also, re: slowing down the game, remember that you will not be going through all ten impulses per turn. You can skip any impulses where no one is moving. Therefore, if there are two ships and one is moving at speed 3 and the other at speed 5, first 5 would move, then both would move (3 moving first), then 5, then 3, then 5, then both - six impulses total.

I like using the impulse chart for movement because it really makes the game feel like the SFU to me. Stripped of the constant interruptions to fire weapons, launch shuttles, or perform various administrative tasks, and pared down to 10 impulses rather than a burdensome and overly-granular 32, I have not found the use of impulse movement to slow the game appreciably at all. It also adds an element of spur-of-the-moment decision making to the game, where you get to react immediately to the sudden (perhaps unexpected) actions of your opponent. If you decide to give it a try, let me know what you think.