toyota gas tank ?s

i got a 94 toyota had a 22r motor. well i need to know what the 3 wires from the sending unit go to there is yellow blue stripe, yellow with red stripe, and black. we think black is ground, red is power and blue goes to guage. corect me if im wrong.
 
also how many gallons is the tank in one. i havent gased it up for 5 years im thinking 15 gal. not shure. but to program my guages i got to set it on empty then put a 1/4 in it then half then full. id like to do this with out filling it up then draining it.

there is 2 tanks ...what is your ex cab or std..why not use water so you can drain it just do let it sit to long

mines ext cab its not a long tank i got it side ways in my rear frame section. its also under the bed now so its alittle more work to get to it now then in the pic. i got it all wired up and ready to go now.   

never mind i just googled it. 13.7 galons if anyone else needs to know.