Warning: This post contains assumptions based on national polling that it is probably not advisable to apply to the Glasgow regional list vote next year.
A poll by YouGov for the Scottish Mail on Sunday published at the weekend put the Scottish parties on the following percentage share for the regional list. Applying that national swing to the Glasgow region we get projected list vote shares of:
Lab 36 47.4
SNP 26 22.8
Con 15 7.2
Lib 12 7.9
Gre 6 6.2
Assuming Labour win all 10 Glasgow constituency seats (sorry Nicola)... (I'm not sorry), that projection leaves us with 4 SNP MSPs, and 1 each for the Liberals, Conservatives and Greens. If either of Labour or the Lib Dems fancied winning the 4th SNP seat, they would need fairly large vote increases. Labour would need an increase of around 15% to a 63% share (highly unlikely), and the Lib Dems would need an increase of around 3.5% to 11.4%.
So if the Liberal Democrats want 2 Glasgow MSPs we can take them by winning over just 1 in 13 of the projected Labour list supporters. Essentially we have to persuade these people that voting for Labour in the list is almost entirely pointless and you should instead be voting for whether you want an extra SNP or an extra Lib Dem representative. I do hope we could point to our successes in previous coalitions with Labour in an attempt to persuade them that switching their support to the Lib Dems would be a canny move on their part.
Obviously all this skullduggery serves to demonstrate just how ferociously abysmal the Scottish electoral system is, but that is an argument for another day.