Yeeeahhhhh... it's not as simple as that. You can't just thrown in any loading schemes/training methods together like that. It took me 3 years to publish the layer system for a reason.
Would 3 x 3 + 8 x 8 work? Maybe. But it would depend on how you perform the 8 x 8. If you see it as 8 hard sets of 8 reps, taking a fairly long rest period between sets to be able to go heavy on the sets of 8, it will likely be too much. The Gironda 8x8 is a density method... basically doing 8 sets of 8 reps with minimal rest (about 20-30 seconds... some of his advanced lifters used as little as 15 sec.) .. basically it's more like one long rest/pause set than 8 distinct sets. As such the load is fairly light and is nothing like 8 regular sets of 8 reps. The Gironda version would likely work, the 8x8 regular sets might be too much. Could be manageable over the short term, but you would hit the wall fast.