Installing Speakers in rear

[Pretender]

I have a VN on gas. The gas tank sits directly under the parcel shelf with no room for speakers of any size to be installed.
I am making speaker boxes for some 6 x 9s and my question is:
Would it be better to make the boxes without a base and cut holes in the parcel shelf or seal the boxes and add tubing from the rear to the front (Bass Reflex) ? Any ideas or dimensions needed if going the bass reflex way.
I will only be running an unamped head unit with quoted power between 35w and 50w per channel. Haven't purchased the head unit yet.
thanks for any advice.

[mouce]

If you're running unampped I'd just put them in sealed boxes. Those figures for the head unit will most likely be 50W MAX which is kinda meaningless. You'd probably be looking at something closer to 20Wrms.

[bezz]

i fit 6x9s in with a small riser nicely... if you fit them in the stock holes in the back corner, the gas tank shouldn't be a problem - it wasnt for me.

[Pretender]

Thanks guys. I think I'll just trim the boxes down to make some risers.