> I do some things that are no longer common in official cards.

Obviously. Your cards look really outdated. The assumption though is that you don't ignore modern design conventions without a reason.

The shuffle rules are in place as they in order to prevent players from knowing the order of the cards in that zone, as well as to prevent them from artificially manipulating that order when an effect wouldn't otherwise allow them to do so. How does your alternative rule set deal with that?

You can try it out with Mirror Gallery, Vitenka.

I'm not sure how many things will go horribly right when you get a second copy of a legend into play; but I kind of want to see it.

All of the rarities of this set are not finalized. The template for TeXnicard sets rarities to common by default, and for many of them, I have not changed them.

Note that mana is not the only purpose of this land. (There are some old land cards that don't add mana at all. I do some things that are no longer common in official cards.) Still, changes are possible; nothing is finalized yet.

Cumulative upkeep is so that the first effect cannot last forever; that was my intention when adding cumulative upkeep.

A land that has cumulative upkeep and can only add mana for a very narrow set of cards is not following the spirit of lands having mana abilities to serve their main purpose as mana sources.

This being a common is also a questionable choice.

I am aware that enchantments don't usually tap, but this time I am using it tapping anyways (although I might change my mind later, since I am not really sure that I will want to violate that convention at this time, although maybe I do).

The echo cost is just an additional cost, like on any other card with echo. (I might remove it if the cost seems unnecessary, though.)

Well, it offers an option to speed up the game by omitting the step of physically mixing up the cards if it is known that doing so is not needed. This rule does not change anything as far as the game is concerned, and is meant to be optional (perhaps I should make that more clear).

(Ignore this variant rule when using any silver-bordered cards together with it, since some depend on physically touching the cards. For the purpose of my variant rules, the cards with physical dexterity effects count as silver-bordered even though they physically aren't.)

No, it isn't meant to be silver bordered. Its supertypes still apply when targeting, searching, etc, and of course it is still historic.

(I admit that this usage is strange, though.)

Ah, probably you are correct.