The 38% rule, in reverse?

Would the "rule" behind this idea still hold up if I sat 38% of the room length from the back wall instead of the front? Id be a fair bet further away from the monitors this way, which I tend to like even though they are only nearfields, and it works better in my room arrangement anyway. If I do it 38% from the front, besides not being as practicle (in my room)as doing it in reverse, it leaves alot of empty room behind me in a room 19ft long. What do you think? thanks.

You could try and measure. That's in fact the only way. This 38% rule is entered on the net by Wes Lachot (a very nice, discrete and gentle guy, which is likely why you hardly hear his name related to this rule, and studio designer) based on an averaged level calculated from the first 4 to 5 axial modes (can't remember) in the length direction. Hence this is a rule of thumb, which does not take anything else into account. In theory this is reversible and can count also for speaker positions in the 3 axises, listening positions in the 3 axises and so on. If e.g. your speakers are at different distances from the walls, you will excite these modes in a different manner which results in another combination, which could alter this 38%. Absorption could alter this % somewhat and so on. Best manner is check the listening and speaker position (if not fixed flush mounted of course). This 38% rule is a very good base to start from. But it's still a rule of thumb only taking few things into account.