Yes, you can move them again. I wouldn't wait until fall, you won't know where they are. When the foliage is about finished dying down, that's when I'd move them, while you can still see them.

When they are in clumps, you can sit a pot over where a clump was, once the foliage is finished, if other plants aren't hanging over that space enough to suit your fancy.

Because you are also concerned about the flower color, you may want to move them when you remember what colors they are. If you don't have enough for fill out the entire area, you can plant in groupings of odd numbers for a decent display pattern also.

I have a relatively small garden about 2 1/2 (maybe 3) feet across next to our walk where we have Tulips soldiered up along the back. But I have them staggered so some are, let's say, 4 inches into the garden and others are 8, so they both have space and appear fuller from the street. In the front of that garden I put pansies in the fall that usually begin to die about now. Then, (in between the pansies on the front and the tulips in the back) I put Profusion Zinnias which eventually mound to fill the entire bed. By the time the Tulips are ready to be trimmed to the ground and the pansies are on their last leg, the Zinnia take over and fill the garden for the summer until October. Now, if you want more than a foot deep of Tulips, then in this garden I'd have problems, because 1) they do not die off soon enough for you to put annuals in for the summer in their place, and 2) Tulip bulbs from what I've read don't like being all that wet, whereas, depending upon the annual, they may need to be watered. So, I just planned the garden wide enough that the annuals and tulips were not using the same space. I actually think the tulips look really nice too after they're finished blooming since, unlike scrawny daffodils, they have really big leaves and such and in my garden at least make a nice background for the otherwise less noticeable pansies.

One of the features of the Omar Sharif rendition of the movie 'Dr. Zhivago' was a mass of yellow daffodils. Money was no object and they must have been planted 4 inches apart.
It has been suggested that you toss the bulbs, a dozen or so, on the ground and plant them where they land. This would give a naturalistic drift effect. I do have clumps where I once planted single bulbs. Time, not money, is the factor, there. I do think, for a future, bulbs must be left to make food for the next Spring, so I tolerate the mess, as they die down. As to tulips, I never succeed in their returning. Perhaps our climate is too hot and humid to leave them in the ground. So I don't usually buy them. Daffodils are coming back stronger and stronger. I can easily see how the dying mass of leaves might be hidden, to a degree, with daylily, taller perennial geranium or tall phlox, if you have a perennial bed. Actually any perennial of two feet or more in height.

bogturtle..your tulips don't come up again the following year? I'm on long island and I've never heard of anyone having problems with them returning year after year. I would think we would be about the same weather-wise, no? Last fall was the first Ive planted in the new home, but the previous owner was a HUGE gardener..at one point...many many many years ago. Most of her garden has since died off but there are a number of areas where her tulips return year after year....even with the house being vacant for a few years prior to us. Many of the tulip bulbs i put in the front yard came up this year....but the backyard was a different story...about 10% probably made it..none of the other plant types came up either. I didn't think much of it until I put in a bunch of lily and gladiola bulbs this spring...only to discover that they were all dug up and eaten, and those not visibly dug up...when i dug down to check...where half nibbled away right where they lay in the holes. wonder if you have some critters feasting on them like they did on mine?