The "hotrodders" say "there's no substitute for cubic inches". Substitute "square inches" and you have the astronomical equivalent.
The 10" has over 1 1/2 times the light gathering power and 1 1/4 times the resolving power. You can always add the computer later.

PS 100 Messier objects is a little steep, there's only 110 of them. 20 or 25 would be a good start.

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Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson