This page tracks Launch 3, planning in progress, a foil balloon launch.

Just the one:

HABTRK

Single Energiser Lithium AA or AAA

AA - 3,000 mah, 15g AAA - 1,250 mah, 8g

Going to use a single AA for my first flight - the voltage drop from a AAA whilst the GPS is getting a fix is quite high and the boost converter I am using fails to maintain the voltage required to the GPS and it resets after a couple of hours in the freezer.

36” Qualatex silver “foil” balloon

Approximate weight of 37g, approximate internal volume of 0.1cu m before envelope stretching.

This means they can lift payloads of approx. 60g (or slightly more if you allow for stretching). However experimenters typically aim for payloads of the order of 20 - 40g per balloon in order to attempt to make them float.

http://www.randomengineering.co.uk/Random_Aerospace/Balloons.html

HABTRK

Looking through the data here: http://ukhas.org.uk/projects:microballoons:data?s[]=foil

and modifying the predictor from here: http://ukhas.org.uk/_media/guides:burst3.xls

with a balloon weight of 37g, a burst diameter of about 0.70m is the best estimate I could make.

Foil balloon float / bursts seem much less predictable than weather balloons, but I will use the above for an idea of the flight path.