Rye, enzymes, texture and taste...

I am very new to sourdough baking.  I have some goals I'm trying to achieve, and although I've been baking good breads I'm dancing around my target without arriving at it.  I worked my way through Forkish's Flour Water Salt Yeast until the pure levain section and now I'm going off into my own territory because his recipes aren't really what I want for my workhorse daily bread recipe.

Here's what I want: a 100% whole grain hearth bread with a soft, open interior, very thin shattery crust, good rise, maximum sweetness and flavor from the grains, and very mild lactic sourness.  I would prefer at least 25% rye.  I bake in an enamel dutch oven.

I struggle with whole grains when the percentage goes above 30% of the total flour.  My crumb closes down more than I want.  It's not dense bread, but it's not what I'm looking for.  As far as dough handling, I'm pretty minimal: I use higher hydrations when the percentage of whole grain increases; I think my last 50% whole grain dough was around 85% hydration.  So I fold during bulk ferment rather than kneading.  I don't THINK my manipulation is the issue. 

I've tried soakers of various time frames and I do believe that helps with texture and flavor.  What I'm curious about is just how much of the total flour in the recipe can be treated this way, and how the rye can figure into the picture best.  I  know there is a point at which the enzyme activity will work against me in the bread's structural integrity and therefore rise.

I've been including rye in both the starter and the soaker, and when I went back to Reinhart's Whole Grain book I noticed the bit about acidity being necessary to control rye's enzyme activity.  So some of my closed textures and lack of full spring are probably from this.

So here is what I'm proposing: a recipe in which the starter represents a large part of the final dough, perhaps 40%.  All the rye in the recipe to be in the starter; and a portion of the remaining flour (all whole wheat) to be made into a soaker 24 hours in advance. 

What I'd like to know, is how much of the remaining flour can be soaked?  How much is too much?  If 80% of the total flour in the recipe is included in the  starter and soaker, will I have a pile of goo at the end?  Should I include some salt in the soaker to counteract this?

Additionally, through trial and error I've realized what I prefer taste-wise is a very short wet ferment of the starter.  2 hours at 166% hydration 70F worked very well for me yesterday with mostly white flour.  This, a comparatively dry final hydration of 65% and a 5 hour room temp bulk ferment, created plenty of rise and a taste I like.  Obviously this is not very much acidity. Will I still run into a gummy texture with rye? 

Obviously the final hydration of my whole grain loaf would have to be higher than 65%.  I'm still not sure HOW high.

I had a kind of thought, of making the rye into a mash to bring out the sweetness, and then scalding the mash after a few hours in order to kill the enzyme activity, then using this mash in the starter. 

What do y'all think?