Can someone with a CZ 40b and a few scope bases help me out?

[Macchina]

I am going to add a picatinny rail to the dust cover of my CZ 40b handgun to mount a flashlight (TLR-3) but don't know what rail to order. Obviously these rails come sized for rifle receivers, so I can't just order a "40b rail". I'm wondering if someone with a 40b can hold a few rifle bases up to the dust cover (in front of the trigger guard) and let me know what rifle contour matches the 40b best. I'd rather have a fit where the base is a bit smaller of a radius than a bit bigger.

I'm hoping to order something like this: http://www.midwayusa.com/product/24...-base-46-gloss?cm_cat=Cart&cm_pla=ProductDesc