Bathtub Installation - New P Trap Doesn't Line Up With Sewage Drain

[Masen]

I'm replacing an alcove bathtub on a slab foundation. Unfortunately, we have to move the location of the drain pipe to make the tub fit. There was an existing hole cut into the concrete and we think we can make this space work. However, we replaced the P Trap and now it doesn't line up with the existing pipe (it's off about 1 inch, see pictures 1 and 2).

Here are the 2 options I'm working with right now. I bought both items and can return the one I don't use.

1. Use a Fernco Coupling to make up for the difference in height? (See pics 3 and 4)
*Is this to code? With this setup, the Fernco will have slight tension pulling up on it in order for the tub drain to reach the bottom of the tub. It seems to fit okay, but I'm worried about that tension in the long run. Also, we will be filling in the space with pea gravel or sand so it's not suspended.

or

2. Use a Slip Joint extension tube between the P Trap and the Tub Drain to raise the tub drain to the proper height. (See picture 5)
*This is the only slip joint extension tube I could find. It seems to be meant for kitchen sinks. Is this okay to be used for tubs? https://www.homedepot.com/p/Everbil...ERCH=REC-_-pipsem-_-205154412-_-205153628-_-N. The existing pipe is ABS and our new tub drain is brass.

Lastly, is there something else entirely I should be doing for this? I have only basic knowledge of plumbing and would love any feedback you guys have. Thank you!

 

[Terry]

I've been using tub drains that glue up. That's a lot of connections there. for a Fernoc type coupling it's best to use something with a metal wrap though.

I normally will assemble a drain on the tub,, remove to install in the ground then measure off the walls and for height and then drop the tub down.