Normally, a hole on a single skin (non-cored) hull can be fixed from one side....the difficulty in this repair is the fact that a structural member is involved, ie, the strake....I would feel more comfortable going from the inside and then finishing from the outside....so maybe go a little more than halfway on the bevel and finish on the other side..the double bevel method is normally used on cored hulls.....and don't bondo the crap out of it either....use glass as far as you can go and only use epoxy putty for fairing at the very end......its a tricky repair, hence I mentioned using the help of the guys on BBC as they have a designer on board to give structural advice.......
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for the forum and....
http://boatbuildercentral.com/
for materials and How To's...that being said, the approach will be the same as I mentioned.....the bevel size you are considering is correct...maybe even take it a little wider....but the "I just glassed the sh+t out of it) is not a good rule to go by. The hull is designed and made to flex as a continuous fiber.....if you glass the sh+t out of it in one spot, your hull will flex differently in that area and may even cause a problem down the road....picture taking a yard stick and holding it on one end and flexing on the other...you see it bend to a certain extent...now grab the yard stick in the middle and try and bend the end....it will react much differently....and thats what will happen if you just build up one area like that...you want to bring it back to its original conformity whenever possible.
You can also go on West Systems web site as they have numerous repair manuals on-line that you can download including a video...Section 4 of the "Fiberglass boat repair and maintenence" manual has some techniques on how to grind out the scarf and how to prep the area and lay back the patches. You can also contact them via email and they normally call you back to discuss your problem...they are very good with customer service like that
But as Macrenovations mentioned, you need to open the glass up and get some good pictures to post....you need to see how far that internal damage really goes as all the crack must be removed before the hole can be repaired....don't rush this...get comfortable with all the information and techniqes as you can before laying and glass.....you will do a much better job on it in the long run...