Drive Medical RTL12075 Folding Universal Sliding Transfer Bench

Can I purchase an extra handle for the bench??

I have severe ra in my hands/arms and don't have enough strength to open a ziplock bag. do you think i would be able to release this to slide?

How can I get a replacement back for this chair ?

Will the frame clear a 20" tub lip? The seat height is listed as 21" to 25" but it doesn't say what the thickness of the seat is above the frame.