Option Tool for use to parcel land sizes wanted

First off I am new to this Landowner stuff and to SL as well, I've only been here for around 5-6 months and just bought land for myself and my group... big step for me, lol.
Here's the question.
Is it just me, and am I missing something when trying to parcel land into different sizes, why do you have no size option available to you?
The reason being that when I try to parcel land into decent sizes for rentals I can't see how you do it... apart from click and drag to 'guestimate' the size, and redo it when it's wrong. I don't want to keep clicking different sizes and joining them either..! I know it may be the way to do it.
Wouldn't it be nice if there was an Option Tool for land sizes when trying to section land into sizes...
512sq mtrs
1024sq mtrs
2048sq mtrs etc etc.
Then you click the size required and click on the area of land you want to set to that size and hey presto... all done. Rather than the click and drag method or setting markers out each time to make adjustments and resizing.
Surely that's not hard to do..... or is it?

Each square when selecting is 16 square meters, or 4 meters on a side. If you know this, you can calculate it by the number of 'steps' it takes pr side. For 1024 meters it'd be 8 steps a side, for 32 meters x 32 meters, and so on.

It's not quite estimating ^-^

ALSO, when selecting land, after it's selected the edit menu shows the total size, just below the 'less' (Hit 'more' to expand) button, but on the left side.

Thanks for the reply Keira,
I know about some of what you say, but I find it a pain to have to keep dragging the landtool to size and if you do mess up you have to do it again. Surely it ain't that hard to add a 'Land-size' tool with different sizes set in place as it would make it so much easier that's all. Then move the 'outline' of the chosen land size to where you want and click on it to set it. You could even parcel up diff shapes too if you want and then click 'fix', 'set' or whatever youwant to call it to add them all in one go, rather than dragging across two parcels to lock them together. Just think how easy that would be to do. Being fussy now, am I? lol

An extra tool function with sub-menus is all it would take, or is there anything available in SL or on SLX that can do this? All I'd like is a nice easy simple tool to use.. and not have to keep doing the click and drag to size the land you want.
Not harping on about this or moaning... I'm just thinking out loud as it were. A pipedream? Well maybe, but it would be nice to have that little extra in the locker as it were.

I don't believe it's possible to script something that can subdivide or join parcels.

However, you could make various blueprint prims, and lay it down, then select the land only under them. Would be a little cumbersome, but get the job done, I think.

@Rorrim

My thoughts where going to the same reason, but my intentions concerning landdividing was if it would be possible to do it with the map. You open it, mark the size and its placement (on the map) and your done. Klick, land has been divided and its placement clean adjusted.
Especially very helpful when your land is hillside and is tumular.