Hi CJ, sorry for the slow reply. There is no guarantees in regards to future share price but doing these envelope studies can give personal expectations of how market will price in a well decision. I've attached a corrected currency model below (goes to show it always pays to triple check others work incase they (I) make a silly mistake).
What I'm doing with this spreadsheet is trying to find a potential risked value for the Wagtail prospect, this is called the Expected Net Present Value or EPV/ENPV. This is the figure that I expect the market to value in to the company once drill funding comes in to prove the prospect. The figure is calculated by using the NPV of a success case multiplied by the COS, in this case the chance of success being 57%. You can model out these values for any prospect of FDR's but it is most fairly used on Wagtail as historical drilling has proven that there is oil there and thus confidence factors put the resource estimate into the contingent category.
I've arrived at an ENPV of 7.2M pound net to finder (20% equity) so I consider it fair to price in around 30% of that once drill funding is secured. I would simple add this 30% to the market cap. I use conservative data assumptions so the market, in theory, should apply a higher value but obviously there are more pertinent factors like marketing and market appreciation for a particular company that will ultimately shape the share price.
TL/DR: With drilling funded for Wagtail I think an FDR MCap of between $16m - $25m is fair. On a successful drill case I think a MCap of $50m - $70m is fair. Just for Wagtail alone.
p.s. let me know if you want me to do some more of these models for other prospects
