Hey Geof,
Long time, no hear from you...welcome back.
Forget the ES-1 driving Maggies in any configuration...the first version hybrid digi amp was incapable of doing so. The 2nd generation F10 is more than capable....based on folks using it on 1.6, 12's and MMG's (including, me) with 2 channels (one fella' here, I can't rember who, use two in a biamp config).
If you tax that wee little power supply too much with too many channels of low sensitivity, 4 ohm loads, it
may not be up to the task. It almost certainly will run hot in doing so. But, it certainly might dependent on a lot of factors.
Therea gret article on JVC's top-of-the-line RX-D702 receiver (150 watts x 7) with the newest, 3rd generation architecture within. You'll note in the power specs that it has prodigeous output in one channel, but grows weaker the more you ask of it.
http://www.soundandvisionmag.com/article.asp?section_id=3&article_id=895&page_number=1So, don't know if anyone can answer your particular questions except you. Look at it this way - it probably WON'T blow up
Get some power conditioning on that over-achieving receiver, too, bud - it's worth the efforts. I have common mode noise (BPT balanced power unit), differential noise (high frequency filters in the BPT and a BrickWall filtering unit placed before it in the chain) and quantum noise (Bybee AC purifiers) all being employed to great effect.
Pretty stupid what you have to do to get a $200 receiver to sound great....but great it does. All that filtration helps all the other components to make better music, too, of course.