You need to do blending. Here is a link to a website with the forumla
http://winemaking.jackkeller.net/blending.asp
So if you brewed a 3.6% lager, you are using 40% tequila and you want a 5.6% outcome, the same as desperados, then you are looking at a ratio of 1.9:34.4. that means for every 34.4 litres of lager, you add 1.9 litres of tequila. Or to put it another way, divide both sides by 34.4 and you get a ratio of 0.056:1, so 0.056 litres of tequila to your 1 litre of lager.
Scale that up, thats 1.285 litres of tequila to your 23 litres of 3.6 % lager.
See, very easy to calculate. The hard think to know is the original strength of the larger using the desperados. Who knows? But lets assume that your coopers kit gets very near the mark. Just brew it really well, aerate well and pitch good yeast (not that sachet of rubish the kit comes with). Make sure your yeast can withstand a 5.6% alcohol environment, otherwise your tequila will steralise the batch and you cant prime it!
I also very much doubt 3.6% is the lager total, so please dont trust my figures, calculate your own when primary fermentation is complete.
I would pitch the tequila at the priming stage.
Now for the lime juice? Hmm, I would add 1 lime per galon in the fermenter. Maybe not enough, maybe too much. You will just have to taste it when its done and see how it turns out. But 1 lime to a gallon sounds good.
Answers.com
http://wiki.answers.com/Q/How_much_sugar_in_a_lime say each lime contains 2 gm of sugar. So when your making your work up subtract 2*number of limes used from your sugar addition. That would be possibly 5 gallons, 10 grams. Doesnt sound much, but go with it for now.
I would DEFINITLY add the lime juice to the secondary rather than the primary. The lime juice has lots of neutrients so it should help kick the fermentation well and get a good FG. Why secondary? The sugars in a lime are different to the sugars in malt, so you want to make sure your malt wort is fully fermented before screwing with the yeast. This should avoid off flavours.
So what have we got?
- make up wort
- 4 weeks in primary at 15°C (if you can)
- Add lime juice to secondary with lager
- 2 months in secondary at 3°C (if you can)
- Move to container, batch prime and add tequila
- 1 month + in the bottle
Last comment, GOOD LUCK!
:drunk: