disclaimer- washes are not my strong point when weathering...
What did you use to thin that enamel based wash? Most folks use high-quality mineral spirits for that as other thinners (lacquer, enamel and generic 'paint thinner') are too aggressive (as you found out).
You can use a solvent-based wash, but I find that fine-tuning it after application is a lot more difficult to control than a water-based wash. Since the solvents evaporate so fast, they leave "tide marks" around details that are hard (for me) to remove or tidy up. They can be used to great effect, but I haven't had that much success with that type..
But the acrylic tube paints from Winsor & Newton are very easy to use over enamels and they should be OK over a thoroughly sealed acrylic paint job. Over a coat of Future, they'll bead up and run right off the paint surface, but a drop or two of dish detergent can break the surface tension so that the wash flows better into the panel lines. The nice thing about using these acrylics is that once dried, they are easily cleaned up with a water dampened cloth or QTip-type ear bud.
If you lay on too much of the water wash, it can (and will) fog or cloud the Future, but can be fixed by sealing in the wash with another coat of Future. Also, this water wash is really fragile, so beware that handling the model so you don't accidentally wipe off all that hard work. I recommend sealing this kind of wash.
But for ease of use and fixability, I would recommend a water-based wash because if it goes all wrong you can just wipe it off.
Don't worry about not knowing this stuff- I'm still trying to figure it out myself! For every good wash-n-weather I get, I have about 3 or 4 bad examples.