ELED

Excuse me for getting low tech and wanting to help you get the job done:

2 suggestions: Power strips/bars and extension cords.

If the fuse won't handle the load, it depends where the fuse is inline, and clearly it's in the inbound portion. I thought it would be elsewhere.

Use 4 per "daisy chain" and burn 10 or 11 outlets via power strips and extension cords.

I mean, if I was under the gun like you are, and I did the math like you did, I'd have come to the same conclusion after about an hour, and then within 15 minutes been off to a hardware store getting parts. My clients aren't paying me for excuses, and I'm sure yours aren't either. Just go get the job done.

The manual CLEARLY states on Page 7 at the bottom(download a copy) that you can daisy chain up to 20 fixtures. Perhaps they mean you can safely run 20 fixtures on a circuit. They also say DO NOT MIX fixtures. With a 3.15amp fuse, there's simply no way that is happening. The manual should be revised.

According to some real fast math:
1800 watts/75 watts = 24. So you could theoretically run 24 of these off of one 15-amp circuit. So, you're going to need at least 2 circuits unless you've got something beefier. I'm fairly sure based on your description you're not pulling wall current.