If rye is really what you have, you can use a product called revolver to help you transition back to bermuda. It is used during the spring transition by professionals to get the cool season turf to die off when the bermuda starts coming back. It is not, however, labeled for us over the top of st augustine. Don't give away trade secrets :>) I don't know about CO, but in TX only licensed professional can use Revolver. Otherwise homeowners have to use granular atrazene formulated for Saint Augustine lawns to do the trick.

Your best idea is the last half..baby shampoo and alfalfa pellets for soil compaction and water retention and just letting the Tiff/Bermuda naturally overtake the annual rye grass.

Reseeding bermuda is not really done in the spring either. You will see a lot of advertising and see giant bags of bermuda seed starting in February but resist the urge. Bermuda seed takes best when the soil is very hot...as in July. What kind of bermuda do you have now? If you have a sodded variety I would suggest you do not seed it under any circumstances. Seeded and sodded varieties are like two different plants. If you mix them, it will always look weedy.

Kurchian, The advice from your local nursery was to plant Annual rye grass with some wildflower seed. The annual rye seed would only grow this year and would not return or re-seed for next year in your zone. This is a quick temporary fix for your bank. To be clear there are different types of rye grass seed, perennial, winter, annual, etc and annual rye grass seed will not return next year or re-seed but will grow quickly with adequate water and sun and could provide a grassy area for this midsummer though fall . I suspect the recommendation for a hydro mat was due to your comment that the area is difficult to water. You might estimate the cost of the mat for your square footage as I suspect it could be pretty costly. What is your long term goal for this area?