OP,
I suspect that you know where the 1.7s were positioned to a very high degree. Having said that I would put the 3.7i's in the same position as a starting point.
Go out and buy a 4'x8' sheet of masonite less than $20:
https://www.homedepot.com/p/Hardboard-Tempered-Panel-Common-3-16-in-x-4-ft-x-8-ft-Actual-0-175-in-x-...
Have them cut it in half.
Now you have two 4'x4' sheets to center under the speakers in the aforementioned placement. Speakers should move very easily as masonite is pretty slick. You won't have any height problems either.
Just a different take on your issue.
Regards,
barts
I suspect that you know where the 1.7s were positioned to a very high degree. Having said that I would put the 3.7i's in the same position as a starting point.
Go out and buy a 4'x8' sheet of masonite less than $20:
https://www.homedepot.com/p/Hardboard-Tempered-Panel-Common-3-16-in-x-4-ft-x-8-ft-Actual-0-175-in-x-...
Have them cut it in half.
Now you have two 4'x4' sheets to center under the speakers in the aforementioned placement. Speakers should move very easily as masonite is pretty slick. You won't have any height problems either.
Just a different take on your issue.
Regards,
barts