Small, economical 4 digit backlit 7 segment LCD timer module

I would like a 4 digit, LCD timer module with a magnetic reed switch. This module including batteries must be as cheap as possible. I require this design to be modified for a smaller LCD GDC0209. PCB will need redesign. Hopefully you can help me. The LCD GDC0209 will be provided to you. Both 12 o'clock and 6 o’clock LCDs will be provided. Form: It is my inetintion for the cost per unit to be as cheap as possible. The purpose of the module is to go inside a cheap disposable gadget. The switch is a 10mm magnetic reed switch (AO) and is securely connected to the back of the module by a 200mm wire (white sheath) with the reed switch at the furtherest point. The reed switch is soldered parallel with the wire. The PCB dimension: length 50mm x width 25mm x depth 30mm. PCB can be deeper/shallower as your design requires. PCB can be longer/shorter as your design requires. Width may not be. The width is very important and must be as narrow as possible. The PCB will require imbedded white LEDs to illuminate the LCD via a diffuser. I would like to investigate the opportunity to have up to 4 more white LEDs within the PCB to illuminate the unit. I would like your feedback on this with regards to power consumption. The LCD will be positioned at the lowest edge of the PCB. LEDs preferred to be above the LCD to enable LCD position to be as close to lowest edge of PCB as possible. The LCD will be in operation in an ambiently lit indoor room. Batteries, as with all other components, must be as cheap as possible (without sacrificing reliability). Coin batteries are preferred given availability and slimness, but am open to your suggestion. Note the unit must be as compact as possible. I would like to hear your estimation for battery life for continuous operation. My aim is to have batteries last at least 7 hours of continuous operation. Obviously I would like more if you can achieve this. Function: When the reed switch is activated the timer LCD screen lights up and counts up in seconds (max 99.99 seconds- ss:th). Accuracy is not important. +-5% is ok. Whole second digits are only visible when counted (I don't want "00.01", the visible digits must be " .01"). Once the timer is deactivated the time continues to be displayed for ~20 seconds. After 20 seconds the power shuts off to the unit, the LCDs shut off and the screen goes blank. Upon activation it resets and begins counting up again from .01. If the timer is interrupted while the LCD is in operation (either counting or displaying the previous count) the module resets and begins counting up again from .01. The timer must enable this interruption. For example: The reed switch has a magnet placed near it, causing it to close. The timer then activates and starts counting up from .01. As the timer is counting the magnet moves away, causing the reed switch to open and break the circuit. The timer pauses counting and displays the time for 20.00 seconds. After 20secs the timer powers down, waiting for the magnet to pass the reed switch again. If the magnet passes the reed switch at any time during the 20sec display time, the timer will begin counting from .01. I am happy to work with you to verify design and functionality over internet and youtube. Once we confirm this I would like you to provide me with 5 individual prototypes for physical testing in Sydney, Australia. Once we have confimed via video then physical test I would like you to provide all supporting documentation. The supporting documentation will be complete and will enable manufacture with the supplier/s of my choice with no ambiguities. If your design and prototypes are suitable in cost and quality I will definitely be interested in a reliable and scalable supplier relationship. I will provide you with LCDs. I am happy to release a milestone payment after agreement of design and components, with full payment upon receipt of prototypes. Your bid must include delivery costs to Sydney, Australia. Good luck guys.