SBL's and bay windows

I will be shortly be receiving my long awaited speaker replacements, with a pair of cherry SBL's arriving.

Now, currently my ageing AE109's (oh to be rid) are placed about 1M from the walls of a bay window, which clears the actual shape of the bay. (If you follow my drift )

With the added complication of having a central heating radiator on the bay wall, where do you recommend I start with my positioning trials with the SBL's?